Sustainable Greenhouse Production Practices - Hydroponics, Aquaponics, and Growing Food Locally

Final Report for YENC09-015

Project Type: Youth Educator
Funds awarded in 2009: $1,986.47
Projected End Date: 12/31/2010
Region: North Central
State: Wisconsin
Project Manager:
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Project Information


Prior to receiving this grant, I was primarily involved in teaching youth about the concepts behind sustainable agriculture, with some hands-on experience for my students. I covered topics like preventing soil erosion, the importance of wetlands for water quality, proper nutrient management - including maintaining water quality by placing buffer strips near waterways, and the importance of being good stewards of the land, both for future generations as well as for farm profitability.

There were multiple goals for this project; the primary goal being to design a watering system for our school greenhouse that conserved water and decreased the need for fertilizer. As a part of this goal, we wanted to explore the benefits of polyculture to decrease fertilizer needs. Our second major goal was for students to explore the benefits of growing food locally by growing food in the greenhouse that can be utilized in the school nutrition program.

Over the past several years, I have noticed that our school greenhouse’s watering system, which was an overhead sprinkler system run by a timer, was very inefficient. The floor was always wet, and algae was always growing on the floor, plants were either too wet or too dry, and our production suffered as a result. At the same time, several retail greenhouses have been popping up around the community, making it difficult for our class to conduct a profitable plant sale. In conjunction with all of this, we were seeing a community interest in growing food locally, our school had gotten involved in the USDA Farm to School program, and our school had hired a new food and nutrition supervisor who is interested in purchasing locally grown food and getting students involved in growing some of the food served in the kitchen. With all of these factors coming together, I viewed it as an opportunity for us to continue using the greenhouse for educational purposes, but in a more sustainable way, and in a way where our students can get involved in the school nutrition program.

The first concern that I had with the greenhouse was the amount of water being wasted with our watering system, and coupled with that, the waste of fertilizer, since we used a fertilizer injector. Since we were planning on moving away from the traditional bedding plant sale in favor of growing fresh fruits, vegetables and herbs, we were able to take a look at various hydroponic systems that would maximize the use of the greenhouse year-round, and achieve our goals of reduced water and fertilizer consumption, and growing food for the school.

I did a lot of research on the Internet about inexpensive hydroponic systems and was able to secure the donation of used 5-gallon pails and 55-gallon drums from a local food processor. Using the donated pails and drums, and a relatively minimal investment in PVC pipe and fittings, sump pumps and timers and perlite as a growing media, we were able to design and build two homemade recirculating hydroponic systems. I also priced commercial systems, and purchased a small educational Nutrient Film Technique (NFT) hydroponic system, and an Ebb and Flow bench system. We were then able to arrange the systems in the greenhouse and have been able to compare their operation.

One other factor that played into the approach we took in this project is a 300-gallon recirculating aquaculture system that we have in our greenhouse. As we clean the tank and biofilter, we noticed that we were releasing a lot of what we suspected was nutrient-rich effluent, and we wanted to capitalize on our aquaculture system as a nutrient source. Our original intent was to transfer the aquaculture effluent into the recirculating hydroponic systems, but students noticed the opportunity to connect the NFT system to the aquaculture system, so we tried that instead.

This entire project has been an excellent learning opportunity for students to build a working production system for plants and to experiment with various nutrient sources, as well as compare between systems. In addition to the things we have already tried, we are looking forward to changing a few things based on what we have learned and modifying the systems to, hopefully, further improve productivity.

Individual, Title, Affiliation, Role
• Sarah Grainger, Water Quality Program Manager, Valley Stewardship Network – presented to students about the impact of agriculture on stream water quality.
• Amber Radatz, SW WI Nutrient Management Specialist, UW-Discovery Farms – presented to students about the effects of farm runoff on water quality and efforts and research being done to limit harmful farm runoff in our region.
• Kevin Masarik, Groundwater Education Specialist, University of Wisconsin – Stevens Point – coordinated groundwater education workshop for teachers, information and materials from which I brought back and taught my classes.
• Laura Chern, Wisconsin Department of Natural Resources (WI DNR) – coordinated groundwater education workshop for educators, information and materials from which I brought back and taught my classes.
• Nicole Penick, Food and Farm Initiative Projects Coordinator, Valley Stewardship Network – presented to students about locally grown food and provided locally grown snacks for students.
• Bjorn Bergman, Vernon Area AmeriCorp Farm to School Coordinator – presented and worked with students to develop a plan for food production for use in the school kitchen
• Nicole Jones, Food & Nutrition Supervisor, Westby Area School District - presented and worked with students to develop a plan for food production for use in the school kitchen
• Reggie Way, Plant Manager, Westby Cooperative Creamery – donated 5-gallon pails and 55-gallon drums for homemade hydroponic systems.
• Lori Martin, Chemistry Instructor, Westby Area High School – worked with us on water quality testing and groundwater quality unit – also attended DNR groundwater education workshop for teachers.
• Various Staff & Community Volunteers, Kickapoo Valley Reserve/WI DNR – helped teach students about water quality with water quality testing, stream invertebrate lab and stream flow rate lab.

Throughout the course of this project, a total of 68 high school agriculture students in Aquaculture, Plant Science and Fish and Wildlife Management classes were directly involved in the project. Students included males and females, from farm and non-farm backgrounds with varying levels of interest in agriculture and environmental conservation.

Through outreach, over 300 Wisconsin agriculture teachers, state staff, business leaders, community members and other agriculture education stakeholders who are members of the Wisconsin Agriculture Education list serve have been informed about the project and have had the opportunity to look at the project on my website. As we take this project into the future and continue further outreach, I expect to reach an even wider community audience.

My students, throughout the course of this project have been able to recognize the ecological benefits and the potential for increased profitability by reducing water and nutrient consumption and making maximum use of available nutrients. Through this project and the guest presentations, students have been able to draw the connection between the work we are doing in the greenhouse and the importance of good nutrient management on their farms, by utilizing manure from their animals and using cover crops as green manure.

As we neared the end of the year, I surveyed my students to determine their understanding and retention of the concepts I hoped to cover in the course of this project.

Some results include:
• 97% recognize Agriculture as one of the major water-using industries in the US.
• 95% recognized that a drip type irrigation system could have more water saving potential than a sprinkler type system.
• 100% recognize that a recirculating irrigation system has the potential to waste much less water than an open irrigation system
• 100% recognize that a recirculating irrigation system has the potential to release much less nutrient load into the surrounding ecosystem
• 100% recognize that using effluent from a fish tank should result in less need for synthetic fertilizer because of the nutrient value in the fecal matter.

Additionally, a summary of student comments on the survey included the following:
• Students recognize that plants, specifically buffer strips and wetlands can be used to filter out pollutants from waterways.
• Students recognize that keeping excess fertilizer from leaving a greenhouse or farm field can keep our drinking water and streams healthier.
• “Our systems control the fertilizer so that it doesn’t get into the outside environment”

Measured from other standpoints, this project has had other beneficial outcomes. From a purely qualitative standpoint, the greenhouse is noticeably dryer, with no standing water or growing algae on the floor. All water used in the greenhouse is either absorbed by the plants or recirculated to a holding bin for future use, with the exception of a slight amount lost to evaporation, which is to be expected in any operation. Similarly, our fertilizer consumption has decreased significantly – by recirculating unused nutrient water, rather than losing it down floor drains from our sprinkler system, we have decreased the amount of fertilizer used by at least 75%. Granted, we are still in an experimental state, with a lower planting density, so a true comparison of nutrient consumption between our project and the original production system is difficult.

There were several things I learned from this project, the first being that the more profitable systems appear to be the ones we designed and built ourselves. With relatively little investment, the two recirculating hydroponic systems we built have shown to produce far better results, with healthier plants, higher planting densities and lower initial cost. The caveat to this is we did not take into account the cost of labor. Because we had a class full of students to help with building the project, and a relatively small educational-scale greenhouse, the cost savings of a homemade system, may not directly translate to a commercial-scale greenhouse.

We ran into problems with the purchased NFT system clogging up, and our lettuce drying up and dying before we caught the problem. Part of this is because we were using fish effluent as the water source, which is less uniform than a prepared fertilizer mix and has a higher potential to clog the small lines of the NFT system. As we proceed into the future with this project, we will be using the commercially prepared fertilizer in the NFT system and the fish effluent in the homemade systems.

We were disappointed with the nutrient quality of the fish effluent. The plants grown using solely fish effluent as fertilizer/water were noticeably paler and less vigorous. Part of this may be because we tapped into the pump used to aerate and recirculate the water in the aquaculture system, rather than power another sump pump. Because of this, the nutrient quality may be lower than we expected. For our next experiment, we intend to flush the fish tank’s biofilter and collect that water, which should have a higher nutrient content.

The students who were involved in this project are definitely very excited about the possibilities of their project. They recognize the benefit of saving water and making maximum use of the resources we have, as well as the excitement of being able to take ownership in this project and to grow food for the school. This project has also helped open them up to the idea of trying something new and experimenting to find a better way to do something. I would definitely recommend any teacher interested in educating about hydroponics to have students research, design and build their own systems.

We are still in the process of sharing information about this project. I am trying to reach local community members and other agriculture educators in Wisconsin about the possibilities for educating about sustainable production, water conservation, water quality, plant science, nutrient management, and the local food movement through hydroponics, aquaponics or some other form of polyculture.

My first major outreach activity was to email the Wisconsin Ag Ed list serve which serves all of the subscribed agriculture teachers in Wisconsin, in addition to state staff, business leaders, community members and other agricultural education stakeholders. I informed them about my project goals, outcomes, encouraged them to explore NCR-SARE, and shared my website with them.

The website is the next major form of outreach. In it we share an explanation of the project, project goals, outcomes, photos, videos, and resources. The website will continue to be live into the future, and we hope to continue to add to it as we continue to explore and do further research. The website is located at: and all project related videos and pictures are included there.

In addition to maintaining and updating the website, my goals for future research include developing a segment for the local community TV channel, and a press release for the local and regional newspaper. I hope to complete this as our crop reaches maturity and we get food into the school cafeteria.

As a participant, it would be helpful if the final report forms were located somewhere on the NCR-SARE website. In my situation, at a public school, it would be beneficial if the term of the grant coincided with the school year and the school’s fiscal year. I have been working with my current classes on the project, but our semester doesn’t end until January 21st, so there are still things I intend to do with the project, even though I am submitting the final report now. Regardless of these relatively minor issues, the project was an excellent opportunity for me as an educator and for my students to experience some hands-on research and education about sustainable agriculture.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.