Progress 10/01/08 to 09/30/13
Outputs
Target Audience: Commercial greenhouse growers in pennsylvania Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? The aquaponics systems are being used for undergraduate independent studies. Each semester 9-12 students have participated in the research project. Initially in design and construction, and in later semesters in management and operation of the systems. How have the results been disseminated to communities of interest? A 1 day workshop was conducted on perennial crop production and greenhouse management in Lehigh County, Pennsylvania. Participants in the workshop were both established commercial producers and potential producers evaluating the business oportunities. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
An aquaponics production system was constructed in a greenhouse on the campus of The Pennsylvania State University. Two replicated aquaculture systems each with a 500 gallon fish production tank were linked to replicated hydroponics systems. Each hydroponic system included a float culture system and a nutrient film trough (NFT) system. Fish tanks were stocked with tillapia. Water from the fish tanks was circulated through the hydroponics systems. Tomatoes, and peppers were grown in the NFT systems and a range of salad greens and herbs were grown in the float culture systems. Water quality was monitored. Plant growth was also monitored. During the construction of the aquaculture systems, the hydroponics systems were used to compare production with an organic fertilizer and standard chemical fertilizers. The theoretical nitrogen content in the 2 systems was identical. The crops grown with conventional fertilizer outperformed the crops provided organic fertilizer. The waste water from the fish was used for hydroponics production once the nitrate concentration in the talk water reached 20ppm. All the crops grown preformed well with the fish waste water except nasturtium where severe iron deficiency occurred.
Publications
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Progress 10/01/11 to 09/30/12
Outputs
OUTPUTS: Continued developments in LED lighting have resulted in reduced cost and increased outputs. These new fixtures have low energy input and generate far less heat than conventional HPS and Fluorescent greenhouse and growth chamber lighting. We have continued to evaluate fixtures in modified growth chambers instrumented to measure energy consumption and environmental conditions. Phillips LED lighting systems previously evaluated in these chambers were replaced with light bars provided by Illumitex with Inventronix 35W LED drivers. The light bars provided a mix of blue and red light. Crops were grown in the growth chamber to evaluate growth and water consumption. These lighting systems were able to produce adequate growth light at a fraction of the cost of the previously used Phillips lighting systems. Water consumption was reduced due to reduced thermal loading. Based on the results in the growth chambers a rack system was constructed to evaluate the use of these lights in the greenhouse to supplement natural lighting. The system was designed to provide approximately 200 umol/m2/s, the same level previously supplied to the test greenhouse bench using HPS lighting racks. The LED lighting rack was used in the greenhouse to provide supplemental light to a research crop grown by the department of Entomology. The rack provided between 195 and 245 umol/m2/s and has proven sufficient for growth of the plants on the bench. Cost of this system was evaluated for potential payback and found to have a ROI of 5 years or less based on electricity consumption, fixture costs and replacement costs for HPS bulbs. In addition maintenance costs were reduced and reliability for growth chambers were improved due to reduced load on cooling compressor systems also contributing to potential ROI for LED implementation. PARTICIPANTS: The Penn State Office of Physical Plant (W.B. Malcom), Theater Arts Program (W. Kenyon, D. Frechen), Horticulture (R. Berghage), Entomology (H. Betz). TARGET AUDIENCES: Penn State Office of Physical Plant, Growth chamber and greenhouse users, Commercial greenhouse and nurseries PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The new fixtures tested in both the greenhouse and growth chambers provided adequate lighting for plant growth at a cost low enough to provide a reasonable return on investment. As a result of this project The Penn State Office of Physical Plant has initiated a project to retrofit campus growth chambers with LED lighting This project will conserve energy, improve reliability of growth chambers and reduce maintenance costs. LED lighting was also shown to be a viable cost effective alternative to HPS in the greenhouse. One limitation to use of the fixtures used in the study in the greenhouse was the requirement for individual drivers for each light strip. This need drove up the cost for the construction of the rack considerably due to the number of weather tight electrical connections used. We will continue to evaluate other potential solutions for use in the greenhouse.
Publications
- No publications reported this period
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Progress 10/01/10 to 09/30/11
Outputs
OUTPUTS: The use of artificial lighting in the greenhouse is limited by the cost and efficiency of the lighting fixtures. High intensity lighting using HID lamps is expensive and the thermal radiation contributes to water use of plants grown with these fixtures. A growth chamber in the Tyson Building on the Penn State University Park Campus was equipped with state of the art LED lighting fixtures and instrumented to monitor energy consumption and chamber environmental conditions. The lighting fixtures used were Philips iW Reach Powercore Architectural Lighting. These fixtures were used because in preliminary research Horticultural LED lighting fixtures were found to have inadequate light output to match the output of standard fluorescent and incandescent lamps used in comparison chambers. Seedling crops were grown in the growth chamber and plant growth and plant water consumption were evaluated. Environmental parameters measured included light level, temperature, and humidity. Chambers were rewired to allow monitoring of power consumption of the chamber for lighting and other uses separately. The experiment used 2 growth chambers and was repeated two times. The LED lighting was transferred between chambers for the 2 repetitions to evaluate the effect of unknown or uncontrolled chamber functions on the results. The results of this project have been shared with the campus Office of Physical Plant and commercial producers and Extension educators in a Farm energy conservation workshop. PARTICIPANTS: This experiment was a unique collaboration between Physical plant, Horticulture and Theater Arts. The Penn State Office of Physical Plant provided assistance, guidance and funding. W. Kenyon from the PSU Theater Arts program and R. Berghage from Horticulture provided assistance and guidance to D. Frechen, a M. Agr. student who completed the research as part of his degree program. TARGET AUDIENCES: Campus Physical Plant, Plant growth chamber users, Commercial greenhouse and nurseries. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Energy consumption by the LED equipped plant growth chamber for lighting was reduced by about 85% and overall electrical consumption by the chamber was reduced by 40% compared to the control chamber. Plant growth was not significantly affected, however plant water use was reduced in LED equipped chambers. The fixtures used were much higher cost (approximately $4,000 each) and light output than currently available horticultural lighting systems and while this project demonstrates the potential for LED lighting, current costs and low light output from horticultural fixtures continue to limit cost effectiveness for commercial greenhouse or growth chamber applications. The fixtures used in this study and electrical use monitoring equipment will be installed in a greenhouse and compared with horticultural HID lighting to measure energy savings and plant growth in a greenhouse setting. Campus Physical Plant is evaluating the potential to switch some of the Horticultural lighting used in greenhouses and growth chambers to LED lighting based on this project.
Publications
- Frechen, D. 2011. The Implementation of LED Technology in Environmental Growth Chambers: Plant Responses, Energy Efficiencies and Practicality of Growth Chamber Retrofitting. M. Agr. Thesis. Horticulture. The Pennsylvania State University, University Park, PA. 45 pp.
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Progress 10/01/09 to 09/30/10
Outputs
OUTPUTS: Energy consumption for heating in the greenhouse is one of the largest expenses for most commercial producers. Commercial bedding plant producers profitability has been increasingly affected by heating costs. Although seasonal bedding plant growers may be less affected by high fuel costs during the winter than a year-round greenhouse production facility, since they may not be heating all their greenhouse space during the colder months of the year, spring heating costs can quickly reduce already thin profit margins. Many bedding plant growers have been examining alternatives to reduce fuel use. For many years, Penn State researchers have been investigating the practicality of utilizing unheated high tunnels for vegetable and cut flower production and season extension for these crops. The research lessons learned suggest the potential for unheated high tunnels to be used as bedding plant production space to partially, or in some cases fully, replace heated greenhouse space. A series of experiments were conducted to determine which plant taxa were sufficiently cold tolerant to be grown in an unheated high tunnel in the early spring; to evaluate relative marketability and cost of production for bedding plants produced in an unheated tunnel compared with those produced in a traditional spring heated greenhouse; and to determine the effect of plug size on time to sale in a high tunnel compared to a traditional greenhouse. One stand-alone quonset style greenhouse on the Penn State campus served as an unheated (high tunnel) for this project. A computer controlled greenhouse section was set to a traditional temperature with heating setpoints of 60 NT and 60 DT and served as the comparison for this project. The ventilation setpoints were (70F Day and night) Nine taxa of plants, with 50 plants per species for a total of 930 plants, were obtained as propagated material grown in 72 plug trays or 125 plug trays (Gro-N-Sell, Chalfont, PA) shipped to Penn State on each of two dates. Liners were transplanted into 4" pots with one-half of the plants placed in a 60 NT greenhouse and the other half moved to the unheated high tunnel. Plant diameter or height and an estimate of commercial salability were determined for each crop. In general, the greenhouse plants flowered and reached salable commercial size first. At the time that the greenhouse grown plant height and width measurement was taken, the diameter of the plants of that cultivar in the high tunnel were also measured to give a sense of the difference in size between the plants grown under the two different temperature regimes when the greenhouse plants were at a salable size. A report was produced and sent to the industry collaborator who has used the information in production and marketing. The results were also disseminated through a greenhouse extension meeting. Students in the greenhouse crop production class participated in the project. PARTICIPANTS: A specialty propagator commercial partner Gro-N-Sell, Chalfont, PA produced all the plugs and starter plant material for this project. They were also involved in the planning and scheduling of the project. Students from the Greenhouse crop production class at Penn State University grew the plants and collected and analyzed data. Dr. Holcomb and Dr. Berghage, Penn State University, worked with the students and the industry partner to coordinate the project and produce the final report. TARGET AUDIENCES: Commercial bedding plant growers. High tunnel vegetable and cut flower producers. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
This project demonstrated the potential for bedding plant production in an unheated high tunnel. Some crops did better in the high tunnel with a large plug; others did better with a small plug in the greenhouse. The best method of production was entirely taxa dependent. Below, each crop has been analyzed according to the data collected to determine the best method of production. It can be determined that in general, the later the plant date, the more useful and effective the high tunnel becomes. In fact, for many of the crops, the pots from in the high tunnel from the second plant date often grew equal or larger in size than the pots grown in the greenhouse. The large plug size produced in the greenhouse was the best option for both plantings of Bellis. Comparing the greenhouse and the high tunnel, the Bellis plants in the greenhouse were saleable a week earlier than in the high tunnel, but the greenhouse plants were thin and tall so the quality of the plants was better in the high tunnel. Surprisingly, the oregano plants from the greenhouse were smaller than the plants from the high tunnel. Since oregano is typically sold later in the season (late April, early May) it would be best to use the small plug in high tunnel production at the second planting date to produce a 4-inch pot of oregano for retail sale. The small Rudbeckia plugs were bushy and taller than plugs grown in the high tunnel. Though they were not in flower, the second planting of small plugs in high tunnel are recommended due to healthy growth and saleable diameter. In this experiment it was generally found that the large plugs of Verbena bonariensis that were grown in the high tunnel were much slower to reach a salable size than the ones in the greenhouse. Wave petunias are grown for their spreading plant habit and showy flowers. These plants prefer warmer temperatures since the greenhouse plants were twice the diameter of the high tunnel plants for the first planting. The second planting in the greenhouse also finished to saleable size one to two weeks ahead of the high tunnel. Lobelia produced saleable plants in the greenhouse and high tunnel; however, the large plugs in the greenhouse produced plants with larger diameters and more flowers. Argyranthemum plants seem to grow best at lower temperatures and reached salable size in a reasonable time in the high tunnel. Space costs for all plants will vary on the amount of time it takes a plant to get to a salable condition. It is estimated the over-head cost of a 60F greenhouse to be $0.25/sqft/week. This would mean that a four inch Verbena Velox would have an overhead cost of $0.17 per pot if grown for six weeks. To grow plants in the high tunnel the space cost would be $0.05/sqft/week. If the same plant grown in the high tunnel for seven weeks would have a space cost of $0.04 per pot. If the space cost for the high tunnel were doubled to $0.10/sqft/week, the space cost per pot in the high tunnel would be $0.08 which is still less than 53% of the space cost in the greenhouse.
Publications
- No publications reported this period
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Progress 10/01/08 to 09/30/09
Outputs
OUTPUTS: The greenhouse industry uses a great deal of growing media since much of the media is used for potted plant production and the growing media is sold with the plants. As new media was developed, the aeration and the water holding capacity were determined, but those tests do not provide any information about water transport within the media. Since many growers are moving toward sub-irrigation, it is becoming important to measure capillary uptake by growing media. We propose to develop a simple and easy way to conduct tests that will compare capillary flow in various types of growing media. The test method evaluated was based on capillary uptake of a growing medium over a specific time course. The preliminary trial was designed to determine the importance of the moisture content of the growing media. In these tests the medium was brought to about 60% moisture content to standardize the effect of initial water content of the medium. The medium was placed in a 3" (7.6 cm) pot and the pot placed in a pan of water that was 1/4" (0.64 cm) deep, with a large volume of water. The objective was to permit the pots to absorb water, but not substantially change the depth of the water in the supply container. The pot was removed and weighed at intervals of 1, 2, 3, 4, 5, 10, 15, and 30 minutes. A regression line was then calculated for each media. The peat was brought to 4 moisture content values (160%, 250%, 390%, and 470%) and pots of moistened peat were placed in contact with water for 30 minutes in a container with the water depth of l/4". The cumulative water uptake was calculated by subtracting the previous weight from the current weight. The peat with the highest mass wetness values (390 and 470) had similar uptake patterns and the intercepts were similar, but the slope of the 390 moisture content line was 0.42 where as the slope of the 470 moisture content line was 0.29. Peat with a moisture content of 250% had a substantially higher slope and a lower intercept while the peat with the lowest moisture content had a steeper slope and a smaller intercept. It is clear then that the initial moisture content of the peat will affect measured unsaturated water flow so any test for capillary flow must standardize the starting conditions. In trial 2 moist peat was compared with perlite and a mixture of 50% peat and 50% perlite. The slope and the intercept of water uptake of peat were similar to that reported in Trial 1. Perlite had a much different intercept and a different slope to the regression line. The mixture of peat and perlite provided an intermediate water uptake. Trial 3 was conducted to provide a comparison of peat, sand, and a mixture of peat and sand. The slope and intercept for sand is much different from either peat or perlite. The water uptake in sand is extremely rapid in that in the first minute all the water that could be taken up was taken up. PARTICIPANTS: At this early stage of the project the participants are Jay Holcomb, faculty, and Robert Berghage, faculty, with Kathy Shumac as the staff person who spends a portion of her time on the project. TARGET AUDIENCES: The target audience for this project is greenhouse growers who use artificial growing mixes in pots and the companies that manufacture artificial growing mixes. There may be limited interest from the nursery industry, but most nurserymen do not use subirrigation so they would have limited interest. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The project demonstrated that different media materials have different capillary flow properties as seen in the different slopes and intercepts. Continued development of a laboratory test that will permit the characterization of unsaturated water flow in commercial growing media is therefore both possible and desirable.
Publications
- Holcomb, J., A. Michael, S. Lenhart, and J. Rowe. 2008. The potential of rice hulls. GPN 8(11):29, 30, 31, 32.
- Papenchak, H., E. J. Holcomb, T.O. Best, and D.R. Decoteau. 2009. Effectiveness of houseplants in reducing the indoor air pollutant, ozone. HortTechnology 19:286-290.
- Holcomb, E.J., R. Berghage, and A. Michael. 2009. High-tunnel pansies. Grower Talks 73(5):70, 72, 74, 76.
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