Source: UNIV OF HAWAII submitted to
CULTURAL STUDIES OF INTENSIVE VEGETABLE PRODUCTION
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0062255
Grant No.
(N/A)
Project No.
HAW00872-H
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Oct 1, 2006
Project End Date
Sep 30, 2010
Grant Year
(N/A)
Project Director
Kratky, B. A.
Recipient Organization
UNIV OF HAWAII
3190 MAILE WAY
HONOLULU,HI 96822
Performing Department
TROPICAL PLANT & SOIL SCIENCE
Non Technical Summary
High quality vegetables are difficult to grow in Hawaii's tropical climate due to high rainfall and soil-related nutritional and disease problems. This study will explore non-circulating hydroponic methods to improve the predictability of growing high quality vegetables in Hawaii. Less expensive, lighter weight and more portable tanks need to be developed for non-circulating hydroponic production of long-term crops. The currently employed suspended pot, non-circulating hydroponic method for short-term, single crops should be adapted to ratoon type crops such as watercress. Raceways utilizing a float-support system for lettuce production could increase production efficiency. Methods need to be developed to reduce the amount of growing medium requirement for rhizome and tuber crops such as ginger and potatoes.
Animal Health Component
(N/A)
Research Effort Categories
Basic
10%
Applied
50%
Developmental
40%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2051310106010%
2051430106030%
2051459106015%
2051460106025%
2051499106020%
Goals / Objectives
1) Adapt an inexpensive nutrient solution tank for growing long-term vegetables by non-circulating hydroponic methods. 2) Adapt the suspended pot, non-circulating hydroponic method to grow ratoon crops and develop a float-support system in a raceway. 3) Develop a sub-irrigation hydroponic system for root and tuber crops.
Project Methods
Greenhouse and field experiments will be conducted at the following University of Hawaii Experiment Stations: Kona, Lalamilo, Mealani, Volcano and Waiakea. In several instances, experiments will be conducted in plastic-covered rainshelters located in a field-setting. These stations range in elevation from 100 m to 1200 m and present a diverse climatic range. In addition, a laboratory is available at the Beaumont Agricultural Research Center to augment the studies at these experiment stations. EC, pH and temperatures of nutrient solutions will be monitored and recorded. The effects of various tank and cover configurations on nutrient solution temperature will be addressed. Total water and nutrient consumption will be recorded and expressed as liters of water and kg of nutrients per 1000 kg of salable crop produced. Ratios of volume available for roots in nutrient solution and moist air will be addressed and calculated. Effects of tank configurations on rooting and crop yields, eg. a pipe vs. a flat-sided tank, will be addressed. Experiments will be conducted as randomized complete block designs with 3 to 6 replications and the number of plants per replication would mostly range between 4 and 10 for long-term crops such as tomatoes, but this could increase to as many as 24 plants for short-term crops like lettuce and watercress. Nutrient solution (2.5 cm depth) would be delivered through 0.3 to 0.6 cm polyethylene tubing to double walled (black on the inside, white on the outside) plastic drain pipes of 10 cm diameter. Tomatoes growing in 3.8 cm net pots would be transplanted into apertures at the top of the pipe. Tests would be conducted with and without adding screen mesh inside of the tube to encourage root growth. Similarly, various small, readily available plastic tanks would also be tested. Another tank system consists of unrolling a thicker plastic sheeting on a level surface and supporting the sides at frequent intervals with plastic pipe or reinforcing rod such that tanks are 30 to 60 cm wide and 15 cm high. These tanks would be used for long term crops including tomatoes, peppers, eggplants and cucumbers. Watercress will be direct-seeded by fluid drilling in a starch base. In addition, both short-term crops and ratoon crops will be grown in net pots supported by expanded polystyrene sheets which float on raceways of nutrient solution and come to rest on fixed supports as nutrient solution is consumed, thus increasing the air space for the roots. Potatoes and ginger will be planted in 36 x 36 x 12 cm trays with a bottom surface that is configured in a lattice-like arrangement with a plurality of square 0.6-cm apertures so the feeder roots can pass through the tray and into the nutrient solution, but allow the storage roots to develop in the tray. The trays will be supported 5 cm above a tank floor. Baby ginger and clean seed production of ginger will be grown in 7.6 and 11.4-liter pots with upside-down, slit-3-liter pots to conserve growing medium and make the pots lighter for handling.

Progress 10/01/06 to 09/30/10

Outputs
OUTPUTS: Annual presentations of non-circulating hydroponic methodology were given to Onizuka Science Day and Higashi Garden Club; multiple presentations were given to Aloha Exchange Club, Hilo Exchange Club, Farm Bureau Farmers Market, UHH CAFNRM classes, Master Gardeners, Penn State Center for Plasticulture and Pennsylvania Ag Progress Days; individual presentations were given to a PBARC ginger meeting, Taste of The Range, CTAHR Centennial Celebration at Mealani Experiment Station, Waiakea Research and Education Center, Malama Aina Festival, Hilo Water Gardening Club and Horticulture Department at Penn State University. Five research papers were presented at three American Society for Plasticulture Congresses. The Best Paper Award was received from The American Society for Plasticulture at the 34th National Agricultural Plastics Congress in Tampa. A research paper was presented at an ISHS Symposium on Soilless Culture and Hydroponics. A seminar was presented to The International Potato Center in Lima, Peru. Email, telephone and face-to-face consultations were made with growers, students, faculty and agricultural professionals. More than 1500 lbs of high quality, clean ginger seed rhizomes were produced in experimental plots and sold to 9 ginger growers. An improved hydroponic plant growing kit was test marketed at Ag Progress Days in Pennsylvania and over 100 kits were sold to participants. A demonstration Wheel Garden comprised of a modified commercial garment rack features 4 different non-circulating hydroponic growing methods including growing tomatoes by a sub-irrigation system, growing cucumbers in a plastic storage container by a suspended pot method, a floating tank cover method for growing watercress and a suspended pot method for growing lettuce and kale. It was exhibited at an open house and a dedication at the Komohana Research and Extension Center. It has been used to train non-circulating hydroponic concepts to Master Gardeners, growers, students and other clientele. At least 20 commercial growers, 10 schools, various clientele of The Hawaiian Homes Program in Hawaii, a community gardening program in New Jersey and a community college program in American Samoa have adopted these new, non-circulating hydroponic growing methods. Hydroponically-produced, gourmet-quality lettuce and watercress is now available in Hawaii. Potential fresh produce food safety issues can be avoided by employing the watercress and lettuce growing methods utilizing domestic water and elevated tanks above a weed fabric ground cover combined with slug control on the ground level. PARTICIPANTS: Bernard A. Kratky, PI; University of Hawaii CTAHR Agricultural Research Technicians Gaillane T. Maehira, Eric Magno, Christopher Bernabe, Roy Ishizu, Milton Yamasaki, Damien Arruda, Marla Fergerstrom, Les Hasegawa, Lori Hasegawa and Earl Arakaki. Partner Organizations: Michael D. Orzolek and William J. Lamont, Department of Horticulture, Penn State University; Mathews L. Paret, Anne M. Alvarez, Randy Hamasaki and Dwight Sato, University of Hawaii CTAHR PEPS Department; Rogerene Arce, Steve Fukuda, Glen Sako and Joanne Lichty, University of Hawaii CTAHR TPSS Department; Dayday Hopkins, County of Hawaii Research and Development; Francis Zee, USDA; Sheldon Furutani, UH CAFRM. Training: Presentations to Onizuka Science Day, Higashi Garden Club, Master Gardeners, Malama Aina Festival, Aloha Exchange Club, Hilo Exchange Club, UHH CAFNRM classes,Farm Bureau Farmers Market, Water Gardening Club, UH CTAHR exhibitions, PBARC ginger meeting, Taste of the Range, American Society for Plasticulture, International Society for Horticulture Science, Penn State University and International Potato Center. Email, telephone and face-to-face consultations were made with growers, students, faculty and agricultural professionals. TARGET AUDIENCES: Vegetable growers, agricultural scientists, agricultural students, primary, and secondary school students, faculty, agricultural professionals, gardeners,community gardens, hobbyists, extension agents and state institutions. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Portable grow beds with roll-out plastic tanks were designed for sub-irrigated, non-circulating hydroponic production of vegetables and edible ginger in remote locations or temporary growing situations. Edible ginger yields from the portable grow bed system were 34 per cent greater than the average yield (2004 to 2008) from field culture. A float-support, non-circulating hydroponic system was developed wherein sheets of extruded polystyrene supported lettuce growing in net pots. Sheets initially floated on the nutrient solution, and then, came to rest on 2 parallel plastic pipes resting on the tank floor as the nutrient solution level receded due to plant growth. Yields from 3 lettuce cultivars growing with this method compared favorably to those growing with a suspended pot, non-circulating hydroponic method where polystyrene tank covers were supported by the 14 cm high sides of the tanks. These passive methods of root aeration enabled lettuce production without electrical power or pumps. Watercress was direct-seeded into 5-cm net pots filled with growing medium at the rate of 10 to 20 seeds per net pot. Doubling the seeding rate increased the yield of the first harvest by 20 per cent, but the ratoon crop yield was not affected. Net pots were supported by extruded polystyrene foam sheets that floated in or were suspended from tanks of non-circulating nutrient solution. In rainshelter-protected trials with 4 original and 4 ratoon crops, watercress yielded 30 kg/sq m of tank at 850 m elevation, and 23 percent lower at cooler 1220m elevation during 8 harvests over a 1 year period. Covering watercress tanks with aluminet or reemay was not warranted and even caused yield decreases in some instances. A shaker seeding method was simpler and more economical than a gel seeding technique. Harvesting may be facilitated by training stem growth in white, 3-liter plastic pots on top of the tank cover, but this reduced yields. A complete crop of watercress can be grown without the use of pesticides in a screened rainshelter. Edible ginger (Zingiber officinale Roscoe) was propagated with vegetative rhizome seed pieces (50 + 10 g) from a previous crop. Seeding material has been maintained free of root-knot nematode (Meloidogyne incognita) and bacterial wilt (Ralstonia solanacearum) throughout 4 growing seasons with passive hydroponic cultural methods. In an outside trial with sub-irrigated pots, a 9.5-liter pot size was too small resulting in competitive yield loss, burst pots and somewhat malformed rhizomes. The highest absolute yields occurred when an upside-down pot was placed in the growing pot and rainfall was diverted by a gutter from pots planted with 3 or 4 seed pieces. Edible ginger, protected by a rainshelter, produced 3.3 kg of rhizomes per sub-irrigated 19-liter pot filled with a peat-perlite medium over an upside-down 3-liter pot. Similar yields were produced with fine cinder, a bottom layer (12 cm) of cinder and a top layer of coir or coir:perlite. Sub-irrigated Yukon Gold potatoes growing in elevated (5 cm), perforated trays filled with 3 liters of peat:perlite growing medium and dry grass yielded 3.2 kg/linear m of tank.

Publications

  • Kratky, B.A. 2010. A suspended net-pot, non-circulating hydroponic method for commercial production of leafy, romaine and semi-head lettuce. University of Hawaii CTAHR VC-1.
  • Paret, M.L., R. Cabos, B.A. Kratky, and A.M. Alvarez. 2010. Effect of plant essential oils on Ralstonia solanacearum Race 4 and bacterial wilt of edible ginger. Plant Disease. 94:521-527.


Progress 10/01/08 to 09/30/09

Outputs
OUTPUTS: Presentations of non-circulating hydroponic methodology were given to The Onizuka Science Day, The Higashi Garden Club, The Malama Aina Festival, The Aloha Exchange Club, The Hilo Exchange Club, UHH CAFNRM classes and a PBARC ginger meeting. A poster on watercress production was prepared for The Taste of the Range and 2 technical papers were presented at The American Society for Plasticulture meeting in State College, PA. Email, telephone and face-to-face consultations were made with growers, students, faculty and agricultural professionals. More than 400 kg of high quality ginger seed rhizomes certified free of root-knot nematode (Meloidogyne incognita) and bacterial wilt (Ralstonia solanacearum) were produced in experimental plots and sold to 4 ginger growers. PARTICIPANTS: Bernard A. Kratky, PI. University of Hawaii CTAHR Agricultural Research Technicians Gaillane T. Maehira, Eric Magno, Christopher Bernabe and Roy Ishizu. Partner Organizations: Michael D. Orzolek and William J. Lamont, Penn State University, Department of Horticulture. Training: Presentations at The Onizuka Science Day, The Higashi Garden Club, The Malama Aina Festival, The Aloha Exchange Club, The Hilo Exchange Club, UHH CAFNRM classes, a PBARC ginger meeting,The Taste of the Range and The American Society for Plasticulture. Email, telephone and face-to-face consultations were made with growers, students, faculty and agricultural professionals. TARGET AUDIENCES: Target Audiences: Vegetable growers, agricultural scientists, agricultural students, faculty, agricultural professionals and gardeners. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Edible ginger (Zingiber officinale Roscoe) was grown outdoors in 9.5-liter pots (with drainage holes) filled with growing medium which nested in 10.3-liter pots with no drainage holes and were constantly sub-irrigated with 5 cm of nutrient solution. The 9.5-liter pot size was too small, and this resulted in competitive yield loss, burst pots and somewhat malformed rhizomes. Vegetative rhizomes from a previous crop were cut into seed pieces (50 + 10 g) for planting the next crop. Seeding material has been maintained free of root-knot nematode (Meloidogyne incognita) and bacterial wilt (Ralstonia solanacearum) throughout 3 growing seasons. The highest absolute yields per pot occurred when an upside-down pot was placed in the growing pot and rainfall was diverted by a gutter from pots planted with 3 or 4 seed pieces. Portable grow beds with roll-out plastic tanks were designed for sub-irrigated, non-circulating hydroponic production of vegetables and edible ginger in remote locations or temporary growing situations. A 1.26 m wide, 20-mil plastic film was rolled out and formed into a channel (45 cm wide and 19 cm high) with the edges folded over and clipped to propagation flats (40 x 40 x 12.7 cm) containing edible ginger and which rested on upside-down nursery trays in a rainshelter. Upside-down, plastic cell-paks (12 cells of 200 cc each) were placed in each flat to reduce the need for growing medium. Yields from the portable grow bed system were 34 per cent greater than the average yield (2004 to 2008) from field culture. A 1.1 m wide, 25-mil plastic film was rolled out and formed into a tank (58 cm wide and 12 cm high). Eggplant, pepper and tomato transplants were grown in 4.2-cm cells of 25 x 50-cm flats resting on upside-down nursery trays (43 x 43 x 6 cm height) in the tank. Pepper transplants were also grown in 10-cm pots and aluminum beverage cans which rested on upside-down trays. Only 340 to 850 ml per plant of growing medium were used for the 3 growing methods. A demonstration Wheel Garden comprised of a modified commercial garment rack features 4 different non-circulating hydroponic growing methods including growing tomatoes by a sub-irrigation system, growing cucumbers in a plastic storage container, a watercress growing system and a suspended pot method for growing lettuce and kale.

Publications

  • Kratky, B., C.I. Bernabe, M. Orzolek and W. Lamont. 2009. Roll-out plastic tanks for sub-irrigation, non-circulating hydroponic systems. Proc. of the 35th National Agricultural Plastics Congress. American Society for Plasticulture, Bellafonte, PA (published on a CD).
  • Kratky, B. and C.I. Bernabe. 2009. Outdoor growing of clean edible ginger seed by a pot-in-pot-in-pot sub-irrigation method. Proc. of the 35th National Agricultural Plastics Congress. American Society for Plasticulture, Bellafonte, PA (published on a CD).
  • Kratky, B., C.I. Bernabe, M. Orzolek and W. Lamont. 2009. Roll-out plastic tanks for sub-irrigation, non-circulating hydroponic systems. Vegetable and Small Fruit Gazette 13(7):4-9.
  • Kratky, B.A., M.T. Yamasaki and R.N. Ishizu. 2008. Low technology hydroponic methods for growing potatoes in Hawaii. Powerpoint presentation given to International Potato Center (CIP) in Lima, Peru. 91 slides. http://www.cipotato.org/csd/materials/seminars/Kratky_Bernie/seminar_ k5.pdf
  • Kratky, B.A. 2009. Three non-circulating hydroponic methods for growing lettuce. Proceedings of the International Symposium on Soilless Culture and Hydroponics. Acta. Hort. 843:65-72.
  • Kratky, B.A. 2008. Three non-circulating hydroponic methods for growing lettuce. ISHS International Symposium on Soilless Culture and Hydroponics. Lima, Peru. Abstract.


Progress 10/01/07 to 09/30/08

Outputs
OUTPUTS: Non-circulating hydroponic presentations were given at the Onizuka Science Day in Hilo, the CTAHR Centennial Celebration at the Mealani Experiment Station, the Waiakea Research and Education Center and the Penn State Center for Plasticulture. A water testing methods class was given to the Hilo Water Gardening Club. Email, telephone and face-to-face consultations were made with growers, students, faculty and agricultural professionals. Two research papers were presented at the American Society for Plasticulture Congress in Tampa. A research paper was presented at an ISHS Symposium on Soilless Culture and Hydroponics in Lima, Peru. A seminar was presented to The International Potato Center in Lima, Peru. The Best Paper Award was received from The American Society for Plasticulture at the 34th National Agricultural Plastics Congress in Tampa. PARTICIPANTS: Individuals: Bernard A. Kratky, PI. University of Hawaii CTAHR Agricultural Research Technicians Gaillane T. Maehira, Eric Magno and Christopher Bernabe. Partner Organizations: Michael D. Orzolek and William J. Lamont, Penn State University, Department of Horticulture. Collaborators: David Tay, International Potato Center, Lima, Peru. Training: Presentations at Onizuka Science Day, CTAHR Celebration at Mealani Experiment Station, Waiakea Research and Education Center and The Penn State Center for Plasticulture. Email, telephone and face-to- face consultations were made with growers, students, faculty and agricultural professionals. TARGET AUDIENCES: Target Audiences: Vegetable growers, agricultural scientists, agricultural students, elementary and high school students, and gardeners. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Sheets of extruded polystyrene containing net pots with lettuce were either supported by the sides of nutrient solution tanks or they initially floated on the nutrient solution, and then, came to rest on 2 parallel plastic pipes resting on the tank floor as the nutrient solution level receded due to plant growth. These methods of root aeration enabled lettuce production without electrical power or pumps. At least 10 active commercial growers in Hawaii are producing lettuce by these non-circulating hydroponic methods. Edible ginger and taro were grown in sub-irrigated 11-liter pots in an unheated Pennsylvania high tunnel. Ginger produced 1.06 kg of air dried rhizomes per pot in a 168 day growing season. Taro produced 0.48 kg of edible leaves and 0.23 kg of edible corm per plant in a 125 day growing season. Yukon Gold potatoes were sub-irrigated with nutrient solution and provided either minimal or no commercial growing medium. Seed pieces were either placed on a paper towel wick over an upside-down nursery tray and covered with dry grass or covered with 250 ml of growing medium plus dry grass. Yields were 3.5 and 5.0 kg/sq m of tank, respectively. Net pots with direct-seeded watercress were placed in floating extruded polystyrene boards. In a rainshelter at 1200 m elevation, the first harvest at 43 days was 1.75 kg/sq m and a ratoon crop after 35 days yielded 4.79 kg/ sq m. Placing a 70% shade screen over the plots resulted in a 65% yield decrease, but a reemay cover increased yields by 17%. At an 800 m elevation, the uncovered treatment yielded 37% more in 13 less days for the 2 harvests and the reemay covered treatment yielded 35% lower than the uncovered control.

Publications

  • Kratky, B.A. 2008. Saving tomatoes from volcanic pollution. p. 127 In B.M. Brennan and J.R. Hollyer eds. Hawaii CTAHR, Celebrating the First 100 Years. University of Hawaii.
  • Kratky, B.A., S.C. Miyasaka, M.D. Orzolek and W.J. Lamont. 2008. Growing taro in a Pennsylvania high tunnel. The Pennsylvania State University Vegetable and Small Fruit Gazette. 12 (2): 3-5.
  • Kratky, B.A., G.T. Maehira, E.J. Magno, M.D. Orzolek and W.J. Lamont. 2008. Growing lettuce by a float-support non-circulating hydroponic method in Hawaii and Pennsylvania. Proc. of the 34th National Agricultural Plastics Congress. American Society for Plasticulture, Bellafonte, PA (published on a CD).
  • Kratky, B.A., M.D. Orzolek and W.J. Lamont. 2008. Production of high tunnel specialty crops in Pennsylvania. Proc. of the 34th National Agricultural Plastics Congress. American Society for Plasticulture, Bellafonte, PA (published on a CD).
  • Paret. M.L., B.A. Kratky and A.M. Alvarez. 2008. Biofumigation with plant essential oils for bacterial wilt management of edible ginger (Zingiber officinale Rosc.) caused by Ralstonia solanaceum Race 4. HortScience 43 (4): 1225. Abstract.
  • Kratky, B.A., M.T. Yamasaki and R.N. Ishizu. 2007. Sub-irrigation methods for growing potatoes in containers under a rainshelter. Acta Hort 747:131-137.
  • Kratky, B.A., M.D. Orzolek and W.J. Lamont. 2007. Yields of edible ginger in a Pennsylvania high tunnel. The Pennsylvania State University Vegetable and Small Fruit Gazette. Vol. 11, No. 12.
  • Kratky, B.A., M.D. Orzolek and W.J. Lamont. 2007. Growing hydroponic cucumbers in a plastic trash container. The Pennsylvania State University Vegetable and Small Fruit Gazette. Vol. 11, No. 11.


Progress 10/01/06 to 09/30/07

Outputs
OUTPUTS: An improved hydroponic plant growing kit was test marketed at Ag Progress Days in Pennsylvania and over 100 kits were sold to participants. A non-circulating hydroponic presentation was made at the Onizuka Science Day in Hilo. A research paper was presented at the American Society for Plasticulture Congress in San Antonio. A seminar was given to the Horticulture Department at Penn State University. Six presentations of ongoing research at The Rock Springs Horticultural Farm were made to groups of 25 to 100 people at the 2007 Pennsylvania Ag Progress Days. Email, telephone and face-to-face consultations were made with growers, students, faculty and agricultural professionals. PARTICIPANTS: Gaillane T. Maehira, University of Hawaii CTAHR Agricultural Technician, Volcano Experiment Station. Eric Magno, University of Hawaii CTAHR Agricultural Technician, Volcano Experiment Station. Christopher Bernabe,University of Hawaii CTAHR Agricultural Technician, Waiakea Experiment Station. Michael D. Orzolek, Professor, Penn State University, Department of Horticulture. William J. Lamont, Professor, Penn State University, Department of Horticulture. Horticulture Department, Penn State University. TARGET AUDIENCES: Vegetable growers, agricultural scientists, agricultural students, elementary and high school students and gardeners. PROJECT MODIFICATIONS: The PI is spending a sabbatical leave at Penn State University from June 1, 2007 through November 30, 2007. The PI continues to work on the project objectives while at this institution.

Impacts
Highest edible ginger yields from sub-irrigated pots occurred when 3 or 4 seed pieces were planted per pot. Growing medium was conserved without a yield reduction of edible ginger when a 3-liter upside-down pot was placed in a sub-irrigated 11-liter pot. Leaching from rain was decreased by placing a gutter over the pots; this increased yields by an average of 0.3 kg/pot. A cellular rooting sponge was substituted for a net pot with growing medium in a previously developed Hydroponic Kit and was re-named as the Plant Growing Kit for lettuce and other short-term crops. Three lettuce types grew with a non-circulating hydroponic system in 14 cm high tanks and similar yields were obtained from continuously floating and float-support treatments. Yukon Gold potatoes growing in perforated trays filled with 3 liters of peat:perlite growing medium and dry grass which rested on 5-cm supports and were sub-irrigated with nutrient solution yielded 3.2 kg/linear m of tank which was greater than other growing medium and cultivar combinations. A portable device was developed to prevent an excessive level of nutrient solution from building up in a drip-irrigated tank. Copper tubing was bent into a form to siphon off excess nutrient solution and the form was stabilized with concrete so that the desired maximum liquid level would be stable. Sub- and drip- irrigated tomatoes growing in 10-cm pots which rested on an upside-down nursery tray yielded higher than tomatoes growing in rain gutters or 7.6-liter pots containing a 3.8-liter upside-down pot and 3.8 liters of growing medium.

Publications

  • Kratky, B.A., M.D. Orzolek and W.J. Lamont. 2007. Growing edible ginger in a Pennsylvania high tunnel. The Pennsylvania State University Vegetable and Small Fruit Gazette Vol. 11, No.8. http://mail.google.com/mail/?ui=1&attid=0.1&disp=vah&view=att&th=1142 d4b4348feba4
  • Kratky, B.A., S.C. Miyasaka, M.D. Orzolek and W.J. Lamont. 2007. Growing taro in a Pennsylvania high tunnel. The Pennsylvania State University Vegetable and Small Fruit Gazette Vol. 11, No.8. http://mail.google.com/mail/?ui=1&attid=0.1&disp=vah&view=att&th=1142 d4b4348feba4
  • Kratky, B.A. 2006. Plastic-covered rainshelters for vegetable production in the tropics. Proc. of the 33rd National Agricultural Plastics Congress. American Society for Plasticulture, Bellefonte, PA. (published on a CD)


Progress 10/01/05 to 09/30/06

Outputs
Edible ginger was planted in non-perforated 11.4-liter pots containing perforated upside-down 3-liter pots to conserve growing medium and these pots were sub-irrigated with 5 cm of 1.5 mS nutrient solution. Yields of 767 and 1509 grams/pot were gathered from pots planted with 1 and 2 ginger rhizomes per pot, respectively. Baby ginger (immature soft rhizomes) was harvested from bottom-perforated, 11.4-liter pots containing similar upside-down 3-liter pots and these pots were sub-irrigated with 5 cm of 1.5 mS nutrient solution from a tank. Yields of 463, 838 and 1238 grams/pot were harvested from pots planted with 1, 2 and 3 rhizomes, respectively. Potatoes were grown in 36 x 36 x 12.7 cm perforated trays resting on a 5 cm plastic support and sub-irrigated with nutrient solution (EC = 1.5 mS). Similar total salable yields (1.5 to 1.7 kg/linear m of tank) were harvested from semi-decayed wood chip medium treatments ranging from 1 liter per tuber (3 liters per tray) to half-full trays of medium (8 liters per tray). Plots were hilled with dry grass. Yukon Gold out yielded (2.0 kg/linear m of tank) All Blue and Red Salad potatoes (1.7 and 1.1 kg/m of tank, respectively). Red Sails leaf lettuce growing in a topcover-supported, suspended pot, non-circulating hydroponic method yielded 336 g/head which was 6 per cent more than lettuce growing in a float-support system in a raceway of non-circulated nutrient solution. Heads in the outer rows of the raceway yielded 17 per cent greater than those in the inner 4 rows when spaced at a density of 16 plants/m2. Raceways were rehydrated prior to harvest such that the expanded polystyrene boards were free-floating. The pulling force required to move 2 boards (1.2 x 1.2m) containing 14.3 kg of lettuce down the raceway to the harvest location did not exceed 1.4 kg. Watercress was grown in open tanks of a complete nutrient solution (EC=1.5mS) which either was completely changed or where about 1/3 (which was lost by evaporation and transpiration) was replenished and the remaining solution was allowed to carryover after each monthly harvest. After 13 consecutive harvests, the carryover treatments had 61 per cent lower yields and 52 per cent lower tissue N content as compared to the treatment which was completely changed after every harvest. Adding 122 ppm N and 0.61 ppm Mn to the following 2 crops of the carryover treatment resulted in yields which were only 33 and 21 per cent lower, respectively, than the treatment completely changed after every harvest. Tissue Cu in the completely changed treatment was 34 pm vs. 25 ppm for the carryover treatment with a corresponding decrease in nutrient solution concentration from 0.32 ppm to 0.02 ppm Cu and this may have contributed to lower yields from the carryover treatment.

Impacts
Mature edible ginger and baby ginger (immature soft rhizomes) yielded up to 1.5 and 1.2 kg, respectively, per 11.4-liter pots which were sub-irrigated with nutrient solution and where upside-down 3-liter pots were employed to conserve growing medium. Potatoes growing in perforated trays resting on 5 cm supports and sub-irrigated with nutrient solution, yielded similarly when either 1 or 2.7 liters of growing medium per seed tuber were hilled with dry grass. Red Sails leaf lettuce growing in a float-support system in non-circulating nutrient solution yielded only 6 per cent lower than when the topcovers were supported in a fixed position by the tank frame. Watercress yields from open tanks where the nutrient solution was only replenished to compensate for transpiration and evaporation losses for 13 consecutive harvests were doubled by 2 applications of 122 ppm N and 0.61ppm Mn to the nutrient solution.

Publications

  • Furutani, S.C., L. Arita-Tsutsumi and B.A. Kratky. 2005. Pyronyl crop spray effective in controlling larvae of the Asian tiger mosquito (Aedes albopictus [Skuse] [Diptera: Culicidae]) in non-circulating hydroponic nutrient solution. Proc. Hawaiian Entomol. Soc. 37:27-31.
  • Kratky, B.A. 2005. Growing lettuce in three non-aerated, non-circulated hydroponic systems. Journal of Vegetable Crop Production. 11(2):35-41.
  • Kratky, B.A., M.T. Yamasaki and R.N. Ishizu. 2006. Sub-irrigation methods for growing potatoes in containers under a rainshelter. Acta. Hort.(In Press).


Progress 10/01/04 to 09/30/05

Outputs
Watercress was grown in open tanks, 2.4 m long x 0.3 m wide x 0.3 m high filled with nutrient solution (EC=1.5 mS) and was harvested every 4 weeks for 13 harvests. Nutrient solution was added after every harvest to replace that lost by evaporation and transpiration. Previous experiments have shown beneficial effects from frequently changing the nutrient solution, but this adds to production costs. Current experimental treatments were: completely change nutrient solution after every second crop, never change the nutrient solution, no nutrient solution change but add 77.5 kg/ha nitrate-N + 25.8 kg/ha ammonium-N + 0.9 kg/ha Mn to every crop, and no nutrient solution change but add 90.4 kg/ha nitrate-N + 12.9 kg/ha ammonium-N + 0.9 kg/ha Mn to every crop. Total yields for the above treatments were 10.55, 5.60, 10.18 and 11.09 kg/m of row, respectively. Thus, it was not necessary to change the nutrient solution after every 2 crops if nitrate-N, ammonium-N and Mn were added to the nutrient solution after each harvest. Potatoes were grown in tanks (3.7 m long x 0.6 m wide) located in a polyethylene-covered rainshelter at an 850 m elevation in Hawaii. Bottom-perforated 8-liter pots containing upside-down 3-liter pots were filled with 5 liters of 3 growing media and these pots were sub-irrigated with 5 cm of 1.5 mS nutrient solution. Total salable yields of 'All Blue' potatoes in peat-perlite, silty clay loam soil or decayed wood chips were 4.9, 2.1 and 5.4 kg/sq.m, respectively. Two methods were compared for growing 'N-52' tomatoes in 5 cm of non-circulating nutrient solution. Plants growing in 3.8 cm diam x 7.6 cm deep net pots which were suspended in plastic rain gutters, and 10 cm pots supported on a 5 cm high screen in a 24 cm wide tank yielded 1.61 and 1.60 kg/plant, respectively, of salable fruit during a 40 day harvest period in plots covered by simple polyethylene rainshelters. Unprotected plants in similar plots were exposed to 118 cm of rainfall during the cropping period and their respective salable yields were reduced 65 and 72 percent. In a non-circulating hydroponic system, lettuce seedlings grew in 5 cm net pots suspended by a topcover on a tank of non-replenished nutrient solution. Unfertilized 2.5 cm foam and sponge blocks were compared with a pre-fertilized, loose, peat-perlite growing medium. In 2 trials, 'Red Sails', a leafy cultivar, harvest weights (186 g/plant) from a peat-perlite medium were 11 and 12 percent higher than when the net pots contained foam and sponge blocks, respectively. Similarly, harvest weight (198 g/plant) of 'Ermosa', a semi-head cultivar, from a peat-perlite medium treatment were 28 and 31 percent higher than from the foam and sponge block treatments, respectively.

Impacts
For hydroponic watercress production in open tanks, it was no longer necessary to change the nutrient solution after every 2 harvests when extra nitrate-N, ammonium-N and Mn were added to a nutrient solution made from a readily available commercial hydroponic fertilizer formulation. An upside-down pot-in-pot subirrigation method for potatoes utilized 37.5% less growing medium and an inexpensive wood chip growing medium resulted in similar yields as an expensive peat-perlite growing medium and this greatly increases the economic feasibility of growing potatoes with this hydroponic method. Tomatoes grew as well in 70 ml net pots in plastic rain gutters as in 700 ml pots in a polyethylene-lined wooden tank.

Publications

  • Kratky, B.A., Maehira, G.T., Cupples, R.J. and Bernabe, C.C. 2005. Non-circulating hydroponic methods for growing tomatoes. Proc. National Agricultural Plastics Congress. 32:31-36.


Progress 10/01/03 to 09/29/04

Outputs
Tomatoes growing in 10 cm square plastic pots were filled with perlite (700 ml) and placed in 24 cm wide, 10 cm high, polyethylene-lined tanks which were sub-irrigated with 5 cm of nutrient solution. Pots rested on 5 cm high upside-down nursery trays which increased the root exposure to moist air (i.e. air between the nutrient solution surface and the tank cover). Mosquitoes were controlled by supporting window screen on the nursery tray above the nutrient solution level, thus trapping newly hatched mosquitoes below the screen where they eventually died. Tomatoes protected by a simple polyethylene rainshelter from 158 cm of rainfall during the growing period yielded 1.75 kg/plant during a 49 day harvest period and unprotected tomato plants yielded 55 percent lower. Similar yields were obtained from rainshelter-protected 7.6 liter pots containing 3.8 liters of cinder growing medium and an empty, upside-down 3.8 liter pot with slits and sub-irrigated with 5 cm of nutrient solution by 4 mm polyethylene tubing. However, no salable yields were obtained when these pots were unprotected from the rain. In a 14 cm high tank containing 5 cm of nutrient solution, potatoes yielded 5.33 kg/m2 from 19 liter bags supported on 5 cm high upside-down nursery trays where seed was planted in 5.7 liters of growing medium and hilled with dry grass and 5.33 kg/m2 when seed was wrapped in newspaper and placed in an upright tray resting on an upside-down tray and covered with dry grass. Several preliminary trials were conducted to determine uniformity of hydroponic watercress growth. Best uniformity was obtained when a shade screen was placed on the west side of a fiberglass-covered greenhouse and when the 0.3 x 2.4 m tanks were oriented in an east-west direction. A ginger field was infected with bacterial wilt (Ralstonia solanacearum) in 2001. Trials this past year (2 years after the infected ginger planting) confirmed bacterial wilt in only 2 of 24 pots and 0 of 3 field plots. Crop rotation (beans, sweet corn and sweet potato) plus the use of organic amendments was practiced in this field. Plants were not hilled as is the normal custom, because root injury from hilling may increase the possibility of infection. Adding a probiotic microorganism mix resulted in more ginger shoots emerging earlier in the growing season. Shoot height and plant vigor ratings of a high lime treatment (1200 g hydrated lime mixed in the soil) was somewhat lower until at least Sept. 23 and this resulted in the lowest average yield per plant. Plants treated with 300 g hydrated lime/pot plus 1500 g organic crumbles were the largest and amongst the most vigorous and gave the highest yield, despite a slight early growth setback.

Impacts
A non-circulating hydroponic method for growing tomatoes which does not support mosquito reproduction has been developed and tested in simple rainshelters and when unprotected from the rain. The first trial gave encouraging results, but technical improvements are needed to improve nutrient flow and increase yields. It was very surprising to learn that bacterial wilt had largely disappeared from an infected ginger field within 2 years. Contributing factors include the use of organic amendments plus crop rotation with beans, sweet corn and sweet potato plus the current ginger crop was not hilled. It is likely that hilling may damage roots and increase the possibility of infection. More early shoots were observed when a probiotic microorganism mix was added to the soil. It is possible to grow hydroponic potatoes by wrapping potato seed in newspaper which has a wick extending into nutrient solution and the plants are hilled with dry grass and this procedure eliminates the need for growing medium.

Publications

  • Hepperly, P., Zee, F., Kai, R., Arakawa, C., Meisner, M., Kratky, B., Hamamoto, K. and Sato, D. 2004. Producing bacterial wilt-free ginger in greenhouse culture. University of Hawaii Soil and Crop Management Series SCM-8.
  • Kratky, B.A. 2004. A suspended pot, noncirculating hydroponic method. Proceedings of the South Pacific Soilless Culture Conference. Acta Horticulturae 648. p.83-89.


Progress 10/01/02 to 09/30/03

Outputs
'Big Beef' tomatoes were grown in 4 inch pots supported by nursery trays in 18 inch wide troughs with 2 inches of nutrient solution. When the top cover was 1 inch thick expanded polystyrene, there were salable yields of 8.28 lb/plant in a 63 day harvest period, whereas a similar system with a black polyethylene top cover only yielded 2.23 lb/plant. The trays were covered with window screen to prevent mosquito production. Pyronyl appears to be an effective mosquito larvicide for commercial non-circulating lettuce growers. One to two ppm of Pyronyl Crop Spray in the nutrient solution controlled the Asian tiger mosquito larvae, Aedes albopictus (Skuse). The mean hrs to LC99 was 36 for 1 ppm and 2.3 for 2 ppm. Pyronyl concentrations from 0 to 0.25 ppm required more than 200 hrs to provide LC99. Lettuce head weight at 5 weeks was not affected by pyronyl concentrations from 0-5 ppm, but a slight reduction in root weight was observed at 5 ppm. 'Catalina' potatoes were grown in plastic bags containing 1.5 gallons of growing medium and 3.5 gallons of dry grass by a subirrigation, hydroponic system. Yields of 1.5 lb/sq. ft were obtained when 2 seed (50 g) pieces were planted per bag. Water consumption was 6.33 gallons/lb of potatoes. Bacterial wilt (Ralstonia solanacearum) on edible ginger has been a serious problem in Hawaii. Infected Soil (10 gallons) was placed in white woven bags and a healthy ginger rhizome (100-125 g) was planted into each bag on May 20, 2002. Plants in the control treatment were dead by Aug. 30. When the soil was amended with 10 g/liter hydrated lime + decaying daikon (50 g/liter) + 10 g/liter of silicon oxide + a microorganism mix, all of the plants survived until the January harvest time. Positive results were also achieved from hydrated lime alone and hydrated lime + silica oxide + a microorganism mix. The silica oxide treatment alone was no better than the control. Thus, it is questionable whether it contributed to the other successful treatments.

Impacts
Very encouraging progress has been made on the ginger bacterial wilt problem by adding various amendments to infected soil. A recommendation was made to hydroponic lettuce growers for an approved insecticide (pyronyl) which may be added to nutrient solutions where mosquitoes are a problem. A sump-sub-irrigation system and the screen method offer alternatives which can eliminate a potential mosquito problem for non-circulating hydroponic growers.

Publications

  • Kratky, B.A. 2003. Growing hyroponic cucumbers in a plastic trash container. University of Hawaii CTAHR Home Garden Series HG-44.
  • Kratky, B.A. 2003. A suspended pot, non-circulating hydroponic method. Acta. Hort. (In Press)


Progress 10/01/01 to 09/30/02

Outputs
'Big Beef' tomatoes grew in a tank with 5 cm of nutrient solution at 3 planting densities. Yields from 10 cm plastic pots resting on 5 cm plastic supports yielded 14 kg/sq m of tank. Yields from aluminum beverage cans with slits on the sides and bottoms resting on the floor of the tank and net pots (3.8 cm diam x 7.6 cm length) supported by the topcover of the tank were 25 and 47 percent lower, respectively. In a fill it and forget it non-circulating hydroponic trial, 12 tomato plants in net pots were transplanted into the tank cover of a 750 liter tank filled with static nutrient solution. Four harvests (24.79 kg) taken at weekly intervals had been completed when the water was depleted for a water use efficiency of 30.54 liters of water/kg fruit. In a sump-sub-irrigation system, nutrient solution flows from a supply tank to a small sump which has a float valve that maintains a 5 cm nutrient solution height which flows outward by gravity through 0.3 cm diameter plastic microtubes to pots with no drainage holes. Tomato yields of 3.6, 2.9 and 3.3 kg/pot were achieved in 12 liter pots containing cinder, perlite and peat:perlite:vermiculite, respectively. Placing an upside-down, empty 3.8 liter pot in a 12 liter pot of growing medium did not lower yields. Potatoes were grown in upright nursery trays resting on upside-down trays (3 tubers/tray) and polyethylene bags (11 and 19 liters with 2 tubers/bag) resting in 5 cm of nutrient solution. Prior to planting, 1.9 liters of potting mix per plant were added to the growing container. The containers were 'hilled' with dry grass as the crop grew. The plant population was 1 plant per 929 square cm of tank space. Total yields of 'Catalina' potatoes propagated from true potato seed were 501, 474 and 423 g/plant from the flats, 19 and 11 liter bags, respectively. Less than 1 tuber/plant exceeded 100 grams for all of the treatments. There were 20.2, 25.4 and 22.3 total tubers/plant for the flat, 19 and 11 liter bags, respectively of which 31, 52 and 42 percent, respectively, were graded in a category that averaged less than 5 grams/tuber. Pepper seedlings were transplanted into net pots (3.8 cm diameter x 7.5 cm depth) in 10 cm high tanks with 5 cm of static nutrient solution at a rainy location. Treatments included nutrient solution EC of 1.5 mS where the plants were protected by a rainshelter and 1.5 and 3.0 mS where the plants were unprotected. The 1.5 mS treatment which was protected by a rainshelter produced 990 grams peppers/plant as compared to only 543 grams/plant from the similar unprotected treatment. The unprotected treatment required twice as much nutrient solution to maintain the 1.5 mS level because rain entered the tank and caused an overflow of nutrient solution. The 3.0 mS unprotected treatment yielded 20 percent lower than the 1.5 mS covered treatment.

Impacts
Grade schools, high schools, colleges, correctional institutions, handicapped groups, hobbyists, senior citizen groups and commercial vegetable growers utilize non-circulating and simple hydroponic technology developed by this project. These systems allow very efficient water use such as the 30.5 liters water/kg of tomatoes reported above. Thus, if water is a limiting production factor, it is possible to predict potential yield. The sump-sub-irrigation system has the potential to replace sub-irrigation systems with static nutrient solution and this would eliminate the potential mosquito problem with its associated health hazards.

Publications

  • Kratky, B.A., Maehira, G.T. and Cupples, R.J. 2002. Shading and periodic replacement of nutrient solution improves production of hydroponically-grown watercress. Proc. Thirtieth National Agricultural Plastics Congress. 30:60-65.
  • Kratky, B.A. and Chia, C.L. 2002. Volcanic air pollution on horticultural crops. Proc. of the Pacific Division American Association for the Advancement of Science 21 (I):39-40.
  • Kratky, B.A. 2002. A simple hydroponic growing kit for short-term vegetables. University of Hawaii-CTAHR Home Garden Series HG-42.


Progress 10/01/00 to 09/30/01

Outputs
Cucumbers, growing in a 200 liter barrel by a non-circulating hydroponic method in Gatton, Australia, required 39 and 50 liters of water to produce 1 kg of fruit in 2 trials, respectively, as compared to only 20 liters at a Volcano, Hawaii site. The evaporation rate at Volcano was 2.7 mm/day and it reached as high as 7.3 mm/day at Gatton. Adding 300 mg nitrate-N to hydroponically-grown lettuce resulted in whole plant nitrate levels of around 700 ppm. Doubling and quadrupling the N application rates increased nitrate-N content by 30 and 43% in a hydroponic system. In a second trial, nitrate-N increased 3(ns) and 24%, respectively, and doubling the nitrate resulted in a yield increase, but quadrupling the nitrate caused a yield decrease. A 138 day tomato crop yielded 2.17 and 2.58 kg/plant when grown in 10 liter, sub-irrigated (7 cm nutrient solution depth) buckets of coal ash and perlite, respectively. Single-plant hydroponic kits for lettuce consist of adding 5 g of hydroponic fertilizer (Chem-Gro 10-8-22) to a 3.8 liter cranberry juice or 5 liter water bottle. Lettuce is planted in growing medium in a plastic net pot (3.8 cm diameter x 7.5 cm long) which is inserted into the 3.9 cm bottle-top opening. No additional fertilizer or water is needed for the crop. In hydroponic watercress trials at 1300 m elevation where nutrient solution was added only to replace evaporation and transpiration, B, Mg, Na and pH increased and nitrate-N, P, Ca, Cu, Fe and Mn decreased in the nutrient solution as the time period between nutrient solution changes increased. Nitrate and Mn levels declined rapidly after the first month. The optimum hydroponically-grown watercress treatment (where the nutrient solution was changed every 2 months) required only about 0.1% as much water (63 liters of water per 1 kg watercress) as watercress grown in a continuously flowing water.

Impacts
A simple hydroponic system has been developed to produce watercress at high elevations. This method only requires 1/1000 as much water to produce a kg of watercress compared to existing methods where watercress is grown in continuously flowing water. Non-circulating hydroponic methods have become a part of some elementary and high school science programs as well as at least 2 State of Hawaii Correctional educational and rehabilitation programs. The increased availability of recyclable plastic bottles with capacities of 3.8 to 5 liters and with a neck size of 3.9 cm allows teachers to assemble a hydroponic kit for each student at a cost of less than $0.50 per kit. This also enhances the hydroponic patents developed by this project since simpler and more inexpensive kits can be designed.

Publications

  • Lichty, J.S. and Kratky, B. 2000. Non-circulating hydroponic culture of anthuriums. Proc. 4th Hawaii Floriculture Industry Conf. University of Hawaii, CTAHR.


Progress 10/01/99 to 09/29/00

Outputs
Plastic trash containers (120 liters) and metal barrels (208 liters) with polyethylene liners were filled with a complete nutrient solution at an electrical conductivity of 2.0 mS. Forestry tubes and plastic net pots containing 'Sweet Slice' cucumbers were transplanted in the containers which were supported by the top covers of the containers. No additional watering, fertilization or monitoring for pH or electrical conductivity was performed throughout the crop. The highest salable yields of cucumber fruit recorded in 5 trials were 7.25 kg for the 120 liter container and 10.63 kg for the 208 liter container. Active growth continued until the nutrient solution was nearly depleted which means the distance between the nutrient solution level and the bottom of the forestry tubes or net pots exceeded 70 cm. Watercress was harvested monthly from open tanks of 30 cm deep and 30 cm wide non-circulating, non-aerated nutrient solution. Yields increased 17 per cent when the nutrient solution was changed following the first ratoon crop as compared to changing the nutrient solution and replanting after every crop. However, the yield of the fifth ratoon crop was only half as great as the first ratoon crop. This indicates that the nutrient solution should be changed and the crop should be replanted prior to the fifth ratoon crop. 'Red Sails' leaf lettuce was grown in 5 cm pots placed in 2.5 cm thick expanded polystyrene sheets which were supported by a 9.5 cm high tank containing non-circulated and non-aerated nutrient solution. No additional nutrient solution was added to the tanks. In 5 trials, yields were reduced by 5 to 26 per cent when the sheets were floated on the nutrient solution and 0 to 10 per cent when the sheets were intially floated on the nutrient solution and then supported at 5 cm above the bottom of the tank.

Impacts
Growing cucumbers in plastic trash containers has already been adopted by several growers and elementary and high school programs. In fact, in a presentation to an American Society for Plasticulture audience, several of the researchers and extension specialists were quite excited about the possibility of demonstrating root growth by this technique to elementary and high school teachers and students in their respective states. There is a need to grow watercress by a method which eliminates the possibility of contamination by water-borne pathogens. This information improves the economic viability of producing hydroponic watercress. The non-circulating hydroponic method for lettuce which has been developed previously by this project has demonstrated a yield advantage over a common float bed horticultural practice for growing several crops. A number of farms plus elementary and high schools have adopted the practice of growing hydroponic lettuce by the suspended pot technique.

Publications

  • Kratky, B.A., Maehira, G.T. and Cupples, R.J. 2000. Non-circulating hydroponic cucumber production in plastic trash containers and polyethylene-lined barrels. Proceedings of the National Agricultural Plastics Congress. 29:210-215.


Progress 10/01/98 to 09/30/99

Outputs
Bush bean plots (60 cm deep lysimeters) were pre-soaked to saturation and then received 0, 0.18 or 0.39 cm/day additional irrigation. Beans in the 0 additional irrigation treatment yielded 0.37 kg/sq m of salable beans, but the other 2 treatments receiving additional irrigation yielded about 4 times more salable beans. Leachates only occurred from the 0.39 cm/day treatment. Nitrate levels in these leachates ranged from 1.9 to 6.2 ppm. In an open-field experiment harvested one day later, the yields from the 3 treatments were 0.65, 1.06 and 1.93 kg/sq m of salable beans, respectively. Hydroponic watercress was grown in 30 cm high x 30 cm wide tanks. Total yield for a 6 month period (April-Sept, 1999) was 8.81 kg/linear m of tank when the nutrient solution was changed every 2 months, but yields were reduced to 7.48 and 5.90 kg/linear m of tank when the nutrient solution was changed every 4 and 6 months, respectively. The September yield was twice as high in plots where the nutrient solution was changed every 2 months as compared to plots where the nutrient solution was not changed for the previous 6 months. The July yield was 1.25 times higher in plots where the nutrient solution was changed every 2 months as compared to plots where the nutrient solution was not changed for the previous 4 months. Concentrations of 25 ppm and greater of Silwet L-77 (silicone-polyether coploymer), a wetting agent, killed mosquito larvae in hydroponic nutrient solutions. 'Red Sails' and 'Green Mignonette' lettuce were grown with a non-circulating hydroponic method and were not affected by 25 ppm Silwet in 4 trials. However, there was a 20 per cent yield decline in 1 of 4 trials at a concentration of 100 ppm Silwet. Passive cooling of a polyethylene-covered rainshelter was addressed. The incoming radiation energy received in one hour at midday on 11/1/98 was equal to 14.1% of the total energy for the day. Evapotranspiration from a hydroponic lettuce crop absorbed 27 per cent of the incoming radiation energy for the hottest hour of the day. The Hargreaves Model estimated that an evapotranspiration cooling potential of about 70% of incoming solar radiation energy could be achieved by misting in the rainshelter. Screening the rainshelter hinders air movement. A 3.3 km/hr breeze was reduced 40 per cent by a 35 per cent shade screen and a 16 km/hr wind was reduced 90 per cent by a 79 per cent shade screen with 0.5 mm openings. A rainshelter is efficiently cooled by venting warm air from the ceiling of the structure. A simple vent may consist of a screened 1 x 2 m opening in the top of the rainshelter which is located so as to minimize rain falling on the plants.

Impacts
Greenhouse and rainshelter operators have been given suggestions regarding passive (not requiring electrical power) cooling of their structures. Watercress may be grown hydroponically and the nutrient solution should be changed every 2 to 4 months. Although 25 ppm Silwet L-77 effectively controls mosquito larvae in nutrient solution, there is still some question about its safety to plants, especially as it concentrates due to evaporation and uptake of the nutrient solution.

Publications

  • Crosby, C.H., Valenzuela, H.R., Kratky, B.A. and Evensen, C. 1999. Evaluation of weed control in a no-tillage vegetable production system. HortScience. 34(3):442.
  • Kratky, B.A. 1999. Considerations for passively cooling a polyethylene-covered rainshelter in Hawaii. Proc. Nat. Agr. Plastics Congress. 28:158-163.
  • Radovich, T.J., Valenzuela, H.R., Kratky, B.A. and Hue, N.V. 1999. Effects of compost and chicken manure soil amendments on basil yield. HortScience. 34(3):551.
  • Valenzuela, H.R., Kratky, B.A. and Cho, J. 1999. Lettuce production guidelines for Hawaii. Knowledge-base CTAHR Web-site http://www.extento.hawaii.edu/kbase/reports/lettuce prod.htm
  • Valenzuela, H.R., Shimabuku, R.S., Kratky, B.A. and Hamasaki, R.T. 1999. Onions in Hawaii and around the world. pp.5-8 in Hamasaki, R.T., Valenzuela, H.R. and Shimabuku (eds.) Bulb Onion Production in Hawaii, University of Hawaii CTAHR, Honolulu.
  • Valenzuela, H.R, and Kratky, B.A. 1999. Soils and soil fertility management for onion production. pp. 9-14 in Hamasaki, R.T., Valenzuela, H.R. and Shimabuku (eds.) Bulb Onion Production in Hawaii, University of HAwaii CTAHR, Honolulu.
  • Valenzuela, H.R, and Kratky, B.A. 1999. Culture and management practices. pp. 15-18 in Hamasaki, R.T., Valenzuela, H.R. and Shimabuku (eds.) Bulb Onion Production in Hawaii, University of Hawaii CTAHR, Honolulu.


Progress 10/01/97 to 09/30/98

Outputs
Edible ginger was grown in tanks containing 5 cm of non-circulating nutrient solution. In trials conducted at 4 locations, ginger yields from nursery flats elevated 5 cm and filled with growing medium were significantly higher in 2 trials, similar in one trial and lower in one trial than yields from 11 liter bags filled with growing medium. Yields were 41% higher when 4 seed pieces were placed in a nursery flat instead of 2 seed pieces. No yield losses were observed in bag treatments where a barrier of sticks and dry grass replaced the upper two-thirds of growing medium. The highest yield in the ginger trials was 12.9 kg/linear m utilizing a 0.6 m wide tank. Hydroponically-grown, greenhouse tomato plants suffered vog (volcanic smog) injury. 'Lenor' and 'Vendor' yields were 50 and 99% lower, respectively, than a similar crop in the previous year which was not exposed to vog. Thus, 'Lenor' demonstrated resistance to vog injury. 'Yellow Granex' onions were grown in greenhouse soil and half of the plots were enclosed in a 50 cm deep polyethylene barrier and half were in open soil beds. Irrigation rates for a 5 month crop were 13.8, 19.6 and 29.5 cm. Outside rainfall was 123 cm. Yields from onions in the plastic barrier were lower than those in the open soil beds. The highest yields came from the highest irrigation rate in the open soil bed treatment that was nearest to the center of the greenhouse. For the lowest irrigation rate, open soil bed plots located near the edge of the greenhouse yielded more than plots near the center of the greenhouse. It can be concluded that at least 15.7 cm of water moved into the greenhouse as groundwater.

Impacts
(N/A)

Publications

  • KRATKY, B.A. (ed.) 1997. Proceedings of the First Non-Circulating Hydroponic Workshop. DPL Hawaii. P.O. Box 6961, Hilo, HI 96720.
  • KRATKY, B.A. 1997. Non-circulating hydroponic methods. in Kratky, B.A. (ed.) 1997. Proceedings of the First Non-Circulating Hydroponic Workshop. DPL Hawaii. P.O. Box 6961, Hilo, HI 96720. pp 2-11.
  • KRATKY, B.A. 1997. Calculating fertilizer rates. in Kratky, B.A. (ed.) 1997. Proceedings of the First Non-Circulating Hydroponic Workshop. DPL Hawaii. P.O. Box 6961, Hilo, HI 96720. pp 43-49.
  • KRATKY, B.A. 1998. Experimental non-circulating hydroponic methods for growing edible ginger. Proc. Nat. Agr. Plastics Congess 27:133-137.
  • KRATKY, B.A., CUPPLES, R., and MAEHIRA, G. 1998. Two-cluster tomatoes require less pesticide per 1000 kg of salable fruit than eight-cluster tomatoes. HortSci. 33:525.


Progress 10/01/96 to 09/30/97

Outputs
Tomatoes were grown in rainshelters at a cool, moist 1300 m elevation by a non-circulating hydroponic method in aluminum beverage cans immersed in a 0.6 m wide tank containing 5 cm of nutrient solution. Tomatoes were pruned such that only 2, 4 or 8 clusters were harvested. Two-cluster 'Vendor' tomatoes yielded 49 and 51 per cent more salable tomatoes per m of tank/year than 8-cluster tomatoes in 2 experiments, respectively. Two-cluster 'Lenor' tomatoes yielded 47 and 69 per cent more salable tomatoes per m of tank/year than 8-cluster tomatoes in 2 experiments, respectively. Two-cluster tomatoes required 347 g of pesticide to produce 1000 kg of salable fruit compared to 708 g pesticide for 8-cluster tomatoes in the first experiment. Fungal pressure increased in the second tomato experiment such that the 2-cluster tomatoes required 1112 g of pesticide to produce 1000 kg of salable fruit whereas 8-cluster tomatoes required 2075 g of pesticide. Most of the pesticides used were fungicides. Edible ginger was grown in a rainshelter at a 500 m elevation by non-circulating hydroponic methods in a tank containing 5 cm of nutrient solution. Ginger was planted in 15 liter pots which were filled with growing medium and were supported by the bottom of the tank; yields of 3.8 kg of rhizomes/bag were obtained. Ginger grown in 43x43x5 cm nursery flats were filled with growing medium and rested upon upside-down empty flats and yields of 4.6 kg rhizomes were gathered from each flat. Ginger growing on upside-down nursery flats without growing medium yielded only 1.0 kg rhizomes/flat.

Impacts
(N/A)

Publications

  • KRATKY, B.A. 1997. Volcanic Air Pollution on Plants. Vog and Laze Seminar Abstracts. University of Hawaii at Hilo Center for the Study of Active Volcanoes.
  • KRATKY, B.A. and SAGER, J.P. 1996. Laboratory Exercises for Growing Plants with the Hydroponic Kit. Grades 1 to 6. Home Hydroponic Systems. Mt. View, HI.
  • KRATKY, B.A. and SAGER, J.P. 1996. Laboratory Exercises for Growing Plants with the Hydroponic Kit. Grades 7 to 12. Home Hydroponic Systems. Mt. View, HI.
  • VALENZUELA, H.R, KRATKY, B. and CHO, J. 1996. Lettuce Production Guidelines for Hawaii. University of Hawaii Research Extension Series 164.


Progress 10/01/95 to 09/30/96

Outputs
In a plastic-covered rainshelter, deficit-irrigated (0.8 cm/wk) 'Red Sails' and 'Green Ice' lettuce yielded 63 and 109% greater, respectively, in unlined soil beds than in polyethylene-lined beds; doubling the irrigation rate increased yields 37 and 77%, respectively, in the polyethylene-lined beds, but no increases were observed in the unlined beds which obtained supplemental moisture from underground soil water movement. The intensity of the red color of 'Red Sails' lettuce is a good indicator of water deficit in the soil. Watercress growing in open tanks (30 cm deep x 30 cm wide) of stagnant nutrient solution yielded 22 kg fresh foliage/m'/year of tank area, but foliage burning occurred. Installing a 50% shadecloth over the tanks eliminated foliage burn without reducing yields. Salable yields of celery were not achieved at irrigation rates below 2.5 cm/wk in open-field lysimeter boxes (60 cm high x 120 cm wide) and the greatest yields (1.53 kg/head) were achieved at the highest irrigation rate tested (4.3 cm/wk). Field- grown 'Crimson Sweet' watermelons died back and dried up shortly after producing their crop, but plants covered with Typar recovered from the die-back and produced new growth and additional, albeit smaller, fruit.

Impacts
(N/A)

Publications

  • KRATKY, B.A. 1996. Non-circulating hydroponic plant growing system. U.S. Patent No. 5,533,299.
  • KRATKY, B.A. 1996. Greenhouse tomato production in top and subirrigated verticalbag culture. Nat. Agricultural Plastics Congress. 26:54-59.
  • KRATKY, B.A. 1996, Non-circulating hydroponic methods. DPL Hawaii, P.O. Box 6961, Hilo, HI.
  • KRATKY, B.A. 1995. Non-circulating hydroponic plant growing system. U.S. Patent No. 5,385,589.


Progress 10/01/94 to 09/30/95

Outputs
Greenhouse cucumbers were grown in aluminum beverage cans with a non-circulatinghydroponic system from February to June (126 days) with a 77 day harvest period. 'Esmeralda' produced 10.2 kg salable cucumbers/plant with a water consumption rate of 13 ml/g fresh wt. of cucumbers. Production of 7 other cultivars ranged from 2.7 to 9.4 kg/plant. In irrigation trials on iceburg lettuce (April-June) and sweet corn (September-December), significant yield and quality losses occurred when the rainfall plus irrigation rates were below 26 mm/week at the Lalamilo Experiment Station. Water leaching losses from 0.6 m deep lysimeters in these trials were not apparent when the rainfall plus irrigation rates were below 33 mm/week. The inner rim on one side of an old tire was removed and a tank was made by lining the tire with polyethylene. A cover was placed over the tank and the forestry tube non-circulating hydroponic method was used to successfully grow lettuce in automobile tires and cucumbers in tractor tires.

Impacts
(N/A)

Publications


    Progress 10/01/93 to 09/30/94

    Outputs
    'Corona' greenhouse cucumbers growing in 0.35 liter beverage cans immersed in 5 cm of aerated nutrient solution yielded 12% more fruit, produced 41% more root dry weight, used 14% more nutrient solution and had a significantly higher uptake of K, Mg, Zn and B, but not of N, P, Ca, S, Mn, Fe and Cu than when the nutrient solution was not aerated. No yield advantage was gained by removing and replacing 2 liters of nutrient solution/plant/week. Aluminum did not accumulate in the tissue of 'Red Fire' leaf lettuce which was grown in new aluminum beverage cans by a noncirculating hydroponic method at pH's of 4 and 6. The same was true for 7 of 8 plants grown in old cans. Presumably, this was due to the protective coatings on the inside and outside can surfaces. 'Yellow Granex' onions were irrigated at 6 rates in a plastic rainshelter with and without a plastic soil barrier. Onion yields from the plastic soil bed barrier treatment were 84 and 46% lower at the lowest irrigation rates of 4.4 and 8.3 mm/week, but were 20 and 76% higher at the highest irrigation rates of 15.8 and 22.4 mm/week, respectively, than the no barrier treatment. Underground moisture movement from outside of the rainshelter and nutrient leaching were suspected to be the causes.

    Impacts
    (N/A)

    Publications


      Progress 10/01/92 to 09/30/93

      Outputs
      'Narukami' Japanese cucumbers were grown by a non-circulating, sub-irrigation hydroponic method wherein 3.7-liter pots, rockwool blocks (7.5 x 7.5 x 6.5 cm block resting on a 15 x 15 x 7.5 cm block) and aluminum beverage cans rested in a covered tank containing 5 cm of nutrient solution. Salable yields were 9.5, 8.2 and 10.1 kg/plant, respectively. In a similar trial, aga Early Green' Japanese cucumbers were grown in 3.7-liter pots, aluminum beverage cans and 160-ml forestry tubes and yielded 4.0, 4.4 and 1.4 kg salable cucumbers/plant, respectively. Five 'Milo' cucumber plants growing in 2.8-liter pots suspended from a lid on a recycled, plastic-lined, 208-liter metal drum produced 11.1 kg of salable fruit/drum. The drum contained 170 liters of nutrient solution throughout the experiment. In a preliminary trial, ginger root yielded over 1 kg of roots per plant when grown in 4-liter pots resting in a covered tank containing 5 cm of non-circulated nutrient solution. A 38-minute videotape was produced; it features forestry tube, screen and sub-irrigated, non-circulating hydroponic methods.

      Impacts
      (N/A)

      Publications


        Progress 10/01/91 to 09/30/92

        Outputs
        An irrigation trial on Hawaiian Supersweet 9A sweet corn was conducted in field lysimeters (2.4 x 1.2 x 0.6 m). Rates of total water applied (irrigation plus rainfall) were 39, 54, 75, 107 and 133 percent of soil saturation. Corresponding yields of salable husked sweet corn were 0.05, 0.99, 1.54, 1.60 and 1.34 kg/m2. Four non-circulating hydroponic methods for growing greenhouse tomatoes consisted of subirrigating 46 x 16 cm and 28 liter pots containing a hapuu:cinder medium and 7.5 x 6.5 cm rockwool blocks resting on a screen or on a 15 x 7.5 cm rockwool block. Salable fruit yields from these treatments were 2.10, 2.94, 2.68, and 2.79 kg/plant, respectively; salable yield from the control soil bed treatment was 2.26 kg/plant. Greenhouse onions were grown in conventional and polyethylene-lined soil beds. Yields near the outside edge of the greenhouse were affected to a lesser extent by these treatments in a dry year than in previous years with high rainfall where there was substantial movement of water into soil beds from outside of the greenhouse.

        Impacts
        (N/A)

        Publications


          Progress 10/01/90 to 09/30/91

          Outputs
          In a greenhouse trial on a coarse aggregated soil, drip-irrigated tomato plants located between 2 rows of the previous crop yielded about 1 kg more salable tomatoes and suffered less damage from rootknot nematode (Meloidogyne spp.) than plants growing in the same row location as previous crops. Greenhouse tomatoes were raised by four methods; in a soil bed, in pots containing a hapuu:cinder mixture which was subirrigated with nutrient solution and in 75 x 65 mm rockwool blocks resting on a screen placed over a 200 mm depth of nutrient solution or on a 150 x 150 x 75 mm rockwool block in 50 mm of nutrient solution. Yields of salable tomatoes were statistically similar from all four treatments. A white plastic mulch promoted earliness of iceburg lettuce which was transplanted on Nov. 7 and harvested on Dec. 27 to Jan. 11. White Plastigone mulch degraded more rapidly than black Plastigone mulch.

          Impacts
          (N/A)

          Publications


            Progress 10/01/89 to 09/30/90

            Outputs
            Three consecutive sweet corn crops were fertilized with digested poultry sludge (DPS) and chemical fertilizer. In the third crop of this regime, sweet corn fertilized with 70 cubic m DPS/ha yielded as well as corn fertilized with the recommended fertilizer rate (280N-184P-115K). Yields increased 16% when this DPS rate was supplemented with one-fourth of the recommended fertilizer rate. In a greenhouse trial, onions were raised in polyethylene-lined soil beds (2.7 x 1.5 m x 0.5 m deep). Yields increased from 20 to 110 ton/ha as irrigation rates increased from 2.3 to 20.6 liters/plant/growing season. Onions in unlined plots yielded higher than those in the lined plots at low irrigation rates because lateral and upward underground water movement supplemented irrigated water; however, lower yields occurred in the unlined, high irrigation plots, because the supplementation of underground water contributed to leaching of nutrients from the root zone. In a greenhouse trial, tomatoes growing in soil beds yielded 6% (ns) more grade 1, 10% (ns) more grade 2 and 41% more offgrade fruit weight than when 2 plants were raised in a polyethylene bag containing 28 liters of 2 cinder:1 hapuu and which was subirrigated with a complete nutrient solution.

            Impacts
            (N/A)

            Publications


              Progress 10/01/88 to 09/30/89

              Outputs
              Iceburg lettuce was grown under a saran-covered greenhouse frame from January toMarch. Plants mulched with black plastic sprayed with aluminum paint matured earlier and yielded 9 percent higher than plants without mulch. In an April-May trial, yields were not increased with a reflective mulch. A labor-saving wire trellis clip was developed. The clip permits additional windings of string around a plant without untying and retying the string. A capillary, non-circulating hydroponic system was developed for leaf lettuce. Forestry seedling tubes, 22 cm long, contained 19-day-old seedlings growing in a sand-peat-vermiculite medium. The lower 2.5 cm of the tubes were immersed in a tank containing 7.5 cm of nutrient solution. No additional watering, fertilization or cultural operations were required except for harvesting the 190 gram heads of lettuce 32 days later. In 2 greenhouse trials at 1300 m elevation, yields of tomato plants growing in plastic bags containing 28 liters of a 1 hapuu:2 cinder medium increased by 48 and 128 percent when the bottom of the bag was slit, thus allowing roots to enter the soil. Plants growing in conventional soil culture yielded an additional 15 percent.

              Impacts
              (N/A)

              Publications


                Progress 10/01/87 to 09/30/88

                Outputs
                Optimum yields (14.1 kgm(superscript 2)) of 'Yellow Granex' onions grown in a rainshelter at 1300 m elevation were produced when onions were drip irrigated with a total of 612 liters water/m(superscript 2). When the water application rate was increased or decreased by 75 percent, yields decreased by 24 and 31 percent, respectively. Yields of rainshelter-protected 'GS-130' tomatoes growing in methyl bromide fumigated soil increased with increasing water rates from 53 to 267 liters/m of row. Daily water application was superior to weekly irrigation. In a soil which had not been treated for nematode control for over one year, root-knot nematode (Meloidogyne spp.) larvae increased 51-fold in the soil as the water application rate to 'Tropic' tomatoes was increased from 49 to 487 liters/m of row; also, severe injury occurred to the plant roots, salable yield was reduced by half and water was clearly wasted at the highest water application rate. When an aluminum foil mulch was applied in a December to February lettuce crop, salable yield increased by 42 percent; however, no yield increase was observed in a May-June trial. Head size of 'Salinas' lettuce increased 16 to 26 percent when the nitrogen rate was increased from 209 to 418 kg/ha, but no significant yield increase was observed with 'Mesa' lettuce in a May-June trial.

                Impacts
                (N/A)

                Publications


                  Progress 10/01/86 to 09/30/87

                  Outputs
                  'Vendor' tomatoes growing in a non-aerated and non-circulating hydroponic systemyielded as well as plants growing in a greenhouse soil bed. When 2 tomato plants grew in a plastic bag containing 28 liters of a 1:2 hapuu:cinder medium, a 39% yield increase was obtained when the roots were allowed to penetrate into the soil below the bags. Plants growing in the greenhouse soil bed yielded 12% more than the most favorable bag culture treatment. An Agronet floating row cover placed over non-trellised tomatoes completely excluded melon flies; a high incidence of melon fly damage to the non-protected control treatment greatly contributed to reducing salable yields to less than 1 fruit/plant. Total bush bean yield was increased by 30% when plants were protected by Shadecloth (55% shade) windbreaks 75 cm high and 3 m apart in a windy area. Iceburg lettuce was transplanted into a 1.2 liter pot which was placed on a soil-cinder bed. Yields were not increased when the pot size was increased to 3.8 liters. Adding 9 grams MagAmp/pot resulted in heads which were firmer and 100 grams heavier; however, salinity injury occurred when the amount of fertilizer was doubled. A peat-cinder medium in the pot was superior to a soil-cinder medium. This pot system of growing lettuce required 9-14 days less in the growing greenhouse than when lettuce was directly transplanted into the soil-cinder beds.

                  Impacts
                  (N/A)

                  Publications


                    Progress 10/01/85 to 09/30/86

                    Outputs
                    AVRDC heat tolerant tomatoes, 'CL 5915-206-2-2-0', produced 0.96 kg/plant more grade 1 fruit when trellised vines were protected by 1.75 m high x 0.8 m wide plastic covered rainshelters during the hot, rainy summer season in Taiwan. Air temperatures under the rainshelters were similar to ambient when the spacing between shelters was 0.7 m and the wind speed was 11 km/hour. Root knot nematodes (Meloidogyne spp.) did not build up in the soil during the cropping period nor in 2 succesive carrot crops when resistant alfalfa cultivars 'Nevada Synthetic XX and YY' were cropped for 29 months. However, very high rootknot nematode buildups and serious yield and quality loss of 2 successive carrot crops occurred when Haifa and common white clover were cropped for 29 months. A new passive hydroponic system does not require movement of nutrient solution. Roots are partitioned into 0(2) and nutrient-water gathering phases. In a preliminary greenhouse trial, 10 tomato plants with roots immersed in a 1 m tank yielded 25 kg fruit at 3 months after transplanting. In a 1200 m elevation greenhouse carrot trial planted in July, 8 or 10 cultivars tested yielded above 3 kg/m of soil bed; 2 of these cultivars yielded above 4 kg/m of soil bed.

                    Impacts
                    (N/A)

                    Publications


                      Progress 01/01/85 to 09/30/85

                      Outputs
                      The principal investigator was away on sabbatical leave during this period.

                      Impacts
                      (N/A)

                      Publications


                        Progress 01/01/84 to 12/30/84

                        Outputs
                        In a windy area, bushbeans protected by a 60 cm high spunbonded polyester (Reemay) windbreak yielded 4 times as much as unprotected bushbeans. This fabric was durable enough to last for only one crop. In a greenhouse carrot trial, 3 cultivars yielded above 6 kg salable carrots/my of soil bed. Carrots were direct-seeded in March and harvested 126 days later. Components of a media formulated for vegetable seedling trays include: 2:3 ratio of hapuu:cinder screened to 4mm or finer, 4 g/liter homogenous 8-32-8 and 2 g/liter dolomite. This media performed as well or better than commercially available media. In a greenhouse trial, 2 tomato plants were grown per plastic bag contining 28 liters of hapuu and cinder. When preplant fertilizers including slow-release fertilizer were used, plants growing in cinder:hapuu with ratios of 1:1 and 2:1 yielded higher than those with an 8:1 ratio. No apparent benefit was gained by adding a water-absorbing gel to the media. A field lettuce trial received 1 cm of water at transplanting and 2.6 cm of rainfall. Two-row beds mulched with plastic yielded 2.81 kg/m of bed whereas unmulched treatments yielded only 2.04 kg/m of bed. Optimum irrigation of these plants (600 ml/plant/day) resulted in yields of 5.65 and 4.71 kg/m of bed for the mulched and unmulched beds, respectively. Reducing the irrigation by one-half reduced yields by 15 and 22 per cent, respectively.

                        Impacts
                        (N/A)

                        Publications


                          Progress 01/01/83 to 12/30/83

                          Outputs
                          Transplanted iceburg lettuce yields per meter of bed per day in the field were 25 to 45 percent higher when 5 and 7.5-cm seedling containers were used, respectively, as compared to 2.5-cm seedling containers. Yields from flat culture and bed culture were similar. More disease (bacterial) occurred on plants mulched with black plastic; this caused a 20 percent reduction in total salable yield. In a deficit irrigation regime on iceberg lettuce, a black plastic mulched treatment required only one-half as much water to attain 80 percent of maximum yield compared to an unmulched treatment. Greenhouse tomatoes growing in a restricted soil bed containing 28 liters per plant of a black cinder:shredded hapuu (2:1) media yielded as well (7 kg/plant) as those growing in a conventional, unrestricted soil bed. Yields decreased to 4.5 kg per plant when the same soil was placed in these restricted beds. Yields from plants growing in cinder:sawdust media were only 5.2-5.8 kg per plant. No ears of 'Hawaiian Supersweet No. 9 and 10' were overature when a one-shot harvest was made within 3 days after one-quarter of the ears matured; however, 75 percent or more were overmature after a 7 day or longer period elapsed.

                          Impacts
                          (N/A)

                          Publications


                            Progress 01/01/82 to 12/30/82

                            Outputs
                            Iceburg lettuce was transplanted into drip irrigated, double row beds mulched with black plastic. All fertilizer was preplant incorporated and one application was sufficient for 3 crops of lettuce; nitrogen (6 g./plant) was supplied in the form of osmocote. In 2 trials, transplanting outyielded direct seeding by 32 and 63% and also 14 and 27 fewer days in the field were necessary when the lettuce was transplanted rather than direct seeded; 5 cm. speedling trays were used in these trials. In drip irrigation trials on iceburg lettuce, the optimum irrigation rate was nearly equal to the total evaporation rate. Although there was a steep rise in yield with increasing water application at the low water application range (less than 0.2 cm./day) it was possible to decrease water application by 20% from the optimum rate without significantly affecting the yield. Eighteen Japanese cucumber cultivars were tested in an unheated greenhouse at 1,300 m. elevation. Based upon a harvest period of nearly 4 months and a spacing of 1.2 X 0.9 m. cultivars which produced over 10 kg./plant included Every Day, Homogreen No. 2 and Tokyo Slicer from the Takii Seed Company and F(1) Hybrid Salad Queen from the Mikado Seed Company. Yields of fresh market 'Tendercrop' bushbean were reduced by 17-28% when a single harvest was taken 7-10 days after the normal first harvesting date as compared to 3-4 multiple harvests taken within a 2-week period.

                            Impacts
                            (N/A)

                            Publications


                              Progress 01/01/81 to 12/30/81

                              Outputs
                              In a drip irrigation trial, optimum yields of lettuce and Chinese cabbage were achieved at irrigation rates of 90 and 100% (3 mm/day), respectively, of evaporation pan readings. A 50% yield reduction was recorded for lettuce when deficit irrigation was practiced (0.75 mm/day). Chinese cabbage suffered a high incidence of tipburn at irrigation rates below 1.5 mm/day. In 2 consecutive greenhouse trials, no significant response was obtained from incroporating 11 and 44 metric tons/ha of macadamia husks into the Manu silt loam soil. A simple PVC arch, 8 m clearspan, polyethylene covered rainshelter suitable for vegetable production in non-windy areas was constructed at a cost of about $4.00/m 2. A suspended cable supports the center of the structure. In a winter iceburg lettuce trial at 800 m elevation, 15% higher yields were produced on beds covered with black polyethylene mulch than on unmulched flat plots. Feasibility trials were established in the windy Kohala area (150 m elevation) which was a former sugar cane production area. The experimental area was protected by wild cane and black saran wind breaks. Saran windbreaks are preferred since they do not generate trash and compete for water and nutrients with the crop. The highest yields obtained include 6.8 kg/m 2 for 'Floramerica' tomato, 0.91 kg/m 2 for 'Kailua' soubean, 2.72 kg/m 2 kg/m 2 for 'Goldinhart' carrots, 2.26 kg/m 2 for 'Greencrop' bushbean and 9.37 kg/m 2 for 'Yellow Granex' onion.

                              Impacts
                              (N/A)

                              Publications


                                Progress 01/01/80 to 12/30/80

                                Outputs
                                Overhead irrigation of watercress leaf temperature and increased yield during summer and fall warm weather on Oahu. Self-pollinating Japanese cucumbers grew successfully in enclosed greenhouses and 500 and 1300 m elevations. Fruits of 4 promising cultivars grew to a length of 25-30 cm and weighed around 200 g; yields of 10 salable kg/plant were recorded. In the first field trial where fertilizer was fed through the drip irrigation system, yields and tissue analysis of 'Floramerica' tomato were not influenced by nitrogen. Salable yields were above 3.6 kg/plant. Presumably, the plot contained residual nitrogen; this experiment will be repeated several times. 'Tropic' greenhouse tomatoes growing in beds of soil 27 cm deep yielded as well as those in a 54 cm depth of soil. When 42% of field grown 'Granex' onions were spoiled at harvest time, only 15% spoilage occurred when temporary fiberglass rainshelters were installed over the onion beds; no differences were observed whether the rainshelters were installed at 0, 1, 2 or 3 mos. after transplanting. 'Green Ice' leaf lettuce grows consistently well in the greenhouse at 1300 m whereas head lettuce types have performed inconsistently. Approximately 200-300 g 'heads' develop within 35-45 days after transplanting.

                                Impacts
                                (N/A)

                                Publications


                                  Progress 01/01/79 to 12/30/79

                                  Outputs
                                  Lettuce: Transplant establishment of container seedlings was retarded when 50-90% of the foliage was trimmed immediately prior to transplanting. Cultivar trials were repeated every 6 weeks at Lalamilo. The better performing cultivars from among the 28 cultivars tested are 'Calmar', 'Great Lakes R-200', 'Gila', 'Great Lakes 366', 'King Crown', 'Red Coach 74A', 'Weslake', 'Salinas', 'Calmaria', 'Cal K-60', and 'Domingos'. Transplanted Yellow 'Granex' onions: At Kainaliu, Kona, a temporary fiberglass rainshelter constructed at transplanting and 1, 2, or 3 months after transplanting reduced the spoilage of onions at harvest time. Cucumber trial on aa lava: After two consecutive cucumber crops, heavy seedling losses due to Pythium were encountered. Conventional chemical control has been poor but a virgin soil method is very promising. Greenhouse tomato: The effect of soil depth and irrigation quantity per application on salinity buildup and yield are being studied. The results of the first completed trial are being analyzed.

                                  Impacts
                                  (N/A)

                                  Publications


                                    Progress 01/01/78 to 12/30/78

                                    Outputs
                                    Cucumber trial on aa lava: When 6 sidedress applications of N-K or N-P-K were added, yield increases correlated with the following preplant fertilizer applications: 400 g chicken manure/hill equal to 400 g chicken manure plus 7.5 g P greater than 7.5 g N-P-K greater than 7.5 g P greater than no fertilizer. Container type and transplant age effects on greenhouse tomato: Generally, 6-10 wk transplants outyielded 4 and 12 wk old transplants. No difference existed between seedling and cylindrical containers. Eight irrigation rates on direct seeded and transplanted lettuce: Untimely rains ruined the data in the first experiment. Preplant and foliar fertilization on lettuce seedlings grown on 6 media types: Optimum seeding weight occurred at 4-8 g/l of 8-32-8 preplant fertilizer. Seedling growth increased with foliar fertilizer rates from 0-1800 ppm 12.5-25-25 plus micronutrients but seedlings appeared lanky and weak at high fertilizer concentrations. Weight increases were observed up to 8 g/l preplant fertilizer were combined with 200 ppm foliar fertilizer, but decreases were observed at all preplant rates combined with 1800 ppm foliar fertilizer. Total harvestable head weight was not affected by media type, but decreases were caused by foliar rates of 600 and 1800 ppm and 32 g/l preplant fertilizer in one experiment. These decreases did not occur on all media in a repeat experiment. It would appear as if foliar fertilization alone is adequate for lettuce seedling production in 2.5 cm speedling trays.

                                    Impacts
                                    (N/A)

                                    Publications


                                      Progress 01/01/77 to 12/30/77

                                      Outputs
                                      Rainshelter construction: A center supported rainshelter (2-1/2 m high x 5 m wide) construted with 1.9 cm schedule 40 PVC arches and a 4 mil polyethylene covering is performing well in two non-windy areas; material cost is less than $2.my. Transplant media and fertilization: Initial tests indicate thay a locally available black sand mixed with peat (2:1) performs adequately as a planting medium; a sugarmill mudcake performed poorly. Better lettuce seedling growth was observed on media fertilized with a granular, homogenous 8-32-8 fertilizer than chicken manure or osmocote (14-14-14) with or without treble superphosphate; a rate of 8 g/1000 cc proved optimum; rates in excess of 20 b/1000 cc decreased seedling size on most media tested, especially if plants were also foliar fertilized. Lettuce seedling growth increased with foliar fertilization (12.5-25-25) at rates up to 225 ppm N but the seedlings appeared to be soft at the high rates. Transplant container: Increasing the speedling tray size from 2.5 to 5 cm cells resulted in approximately a doubling of 3-5 week old lettuce seedling weight, depending upon the media used. Greenhouse tomato cultivar trial: Yields above 4 kg/plant were obtained with 6 of 20 cultivars tested in a February-June planting in an unheated greenhouse at 1300 m elevation where average nightly lows of 8-11 degrees C prevail; the percentage grade one fruits was low for all cultivars.

                                      Impacts
                                      (N/A)

                                      Publications


                                        Progress 01/01/76 to 12/30/76

                                        Outputs
                                        Crop rotation: No significant yield increase was obtained on greenhouse tomatoes by planting onion, bush beans and semi-head lettuce for 6 months in an area which previously was planted to 3 successive tomato crops. Greenhouse tomato variety trial: A February planting in an unheated greenhouse at 4000 ft.elevation proved unsatisfactory for all 19 varieties tested where high humidity and overcast weather persisted. However, a number of varieties are performing well in a June planting at the same location. Rainshelter construction: Construction of simple inexpensive arched PVC greenhouses with a center support may prove feasible for non-windy areas. Thinner grade PVC pipe should be avoided since breakage or permanent bends may occur at shear points. Lettuce and Chinese cabbage fertility trial: Fourteen N-P-K combinations ranging from nofertilizer to 180-75-300 lb/A/crop failed to provide significant yield differences for 2 successive trials on a previously cropped Waimea silt loam soil. Cabbage: In a preliminary study of the data of a continuous function, greenhouse trial, an optimum irrigation rate (0.25 cm/day) and N use (1.9 g N/plant) were similar to that of lettuce in a previous trial.

                                        Impacts
                                        (N/A)

                                        Publications


                                          Progress 01/01/75 to 12/30/75

                                          Outputs
                                          Plastic tunnels: Increased earliness and yield were obtained on repeated late winter plantings of cucumber, pepper and tomato. Wind protection was evident. The incidence of mosaic disease to pepper was greatly reduced. Long-term fertilizer trial: The effects of repeated applications of 14 fertility variables are being tested on two varieties of lettuce and Chinese cabbage in the first trial the no fertilizer treatment performed as well or better than theother treatments. Lettuce: Maximum yield response occurred at 1.9 g N/plant & an irrigation rate of 0.25 cm/day in a continuous function greenhouse trial employing 6 N rates ranging from 0-4.6 g/Plant and 6 irrigation rates ranging from 0-0.6 cm/day. Greenhouse tomato: UH varieties N-91 and N-93 yielded as well as Tropic (5.5-6.0 kg/plant/6 months) in a variety trial. UH N-91 and N-93 have the added advantages of greater disease resistance, less vegetative growth and a one week earlier maturity. Yield was not affected when soil moisture level was maintained at 20 or 60 centibars until fruit formation on the second cluster after which soil moisture level was maintained at 20 centibars.

                                          Impacts
                                          (N/A)

                                          Publications


                                            Progress 01/01/74 to 12/30/74

                                            Outputs
                                            Chinese cabbage: A disease causing yellowing and decreased vigor is being explored. The cause has not yet been found. Greenhouse lettuce: A continuous function experiment employing six nitrogen rates and six irrigation rates is ongoing. Greenhouse tomato: Osmocote proved as effective as weekly liquid feedfertilizer application; however, the Osmocote cost would be greater. Yields increased with increasing nitrogen rates for the first crop but not for the second crop. The electrical conductivity (EC(E)) of soil decreased as the amount of water applied increased. Higher EC(E) readings were obtained with three levels of trickle irrigation than three levels of basin irrigation on a porous soil. Yield was highest at the wettest soil water content (0.20 bars). Yield of Tropic Tomatoes decreased 50% at EC(E) readings of 7 and 11 on an unlimed and limed soil, respectively. Mulch trials: Clear polyethylene increased earliness and aluminum foil decreased earliness on cantaloupe. Outside tomatoes: The yield response to starter and sidedress nitrogen applications is being investigated. Plant growing media: New plant growing media were developed from irreversibly dried, locally available, Akaka and Mealani soils. They were successful in rooting and seedling media, respectively. Plastic row covers: Increased earliness, yield and considerable wind protection were obtained in initial trials on cucumber, pepper, and tomato.

                                            Impacts
                                            (N/A)

                                            Publications


                                              Progress 01/01/73 to 12/30/73

                                              Outputs
                                              BURDOCK: A satisfactory summer yield of 15,000 lbs. roots/A was obtained in a yield feasibility trial at a 4,000 ft. elevation. CELERY: Heart rot incidence was greatly reduced by sprays of 0.25% Calcium as calcium nitrate and calcium chloride but was decreased only slightly by a heavier irrigation rate. PLANT GROWING MEDIA: A new plant growing media using locally available raw materials is being developed and tested. RAINSHELTERS: An air pillow roof structure has been constructed and is being evaluated. The possibility of using guava arches for constructing inexpensive commercial sized rainshelters is being explored. SOLAR HEATING: An inexpensive solar heater is being developed and tested for greenhouse heating. TOMATOES - FIELD: Four starter and maintenance nitrogen levels are being evaluated with respect to yield and tissue analysis. TOMATOES - GREENHOUSE: A third osmocote vs continual feed fertilizer trial is ongoing. Asalt tolerance trial on a tropical soil is ongoing. Tomatoes growing in greenhouse beds infested with bacterial wilt died whereas all those growing in virgin soil placed in plastic containers located directly over the infected soilbeds remained healthy. Yield increased with increasing densities and with the use of clear plastic and aluminum foil mulches in an unheated greenhouse at 4,000 ft. elevation.

                                              Impacts
                                              (N/A)

                                              Publications


                                                Progress 07/01/72 to 12/30/72

                                                Outputs
                                                Several experimental plastic rainshelters were constructed. They consist of bamboo or guava arches or rafters covered by plastic. The rafters are either placed directly in the soil or on a structure. In preliminary trials, tomatoes were protected from bacterial wilt by placing the roots in a container with uncontaminated soil. The following experiments are in progress; Celery: The effects of three rates of drip irrigation and two calcium sprays are being tested in an effort to eliminate heart rot. Greenhouse lettuce: Drip irrigation levels are being compared in an effort to attain optimum yields. Greenhouse Tomatoes: Residual effects of 9 rates each of N and K from a previous crop are being evaluated. Yield potentials at three densities with aluminum and plastic mulches are being explored. Nine rates of liquid feed fertilizers are being compared with nine rates of osmocote using three varieties. Water use data from several sites is being collected.

                                                Impacts
                                                (N/A)

                                                Publications