Improved Productivity in Winter Greenhouse

2007 Annual Report for FNC06-642

Project Type: Farmer/Rancher
Funds awarded in 2006: $1,565.00
Projected End Date: 12/31/2008
Region: North Central
State: Minnesota
Project Coordinator:

Improved Productivity in Winter Greenhouse


Grant funds were used to purchase the materials needed to construct a raised bed in the greenhouse. Materials included a raised bed kit from FarmTek which uses side walls made of heavy-duty pond liner material that has sewn-in sleeves to accommodate the metal posts that secure it to the ground along the perimeter of the beds. The kit was designed to construct one long raised bed but we needed to adapt it to our bed layout in the greenhouse, which took some adjusting but was do-able. We found the materials to work quite well. It has held up just fine and is a rather clever way to expand the use of a material created for an entirely different purpose. I would recommend this material to others who want to have a low-cost way to create raised beds that can also be easily disassembled and relocated if needed. I will continue to monitor how this raised bed system holds up in the greenhouse environment.

We purchased a considerable amount of soil amendments (top soil, peat and compost) to match the composition of the soil in the regular beds of the greenhouse. I underestimated the amount of soil materials that would be needed to create the raised bed and went over budget on this cost, so will have to compensate in other areas.

Soil heating cables were purchased which were attached to metal cloth that was placed in the raised bed with an additional 6 inches of soil materials placed on top of the heating cables. A temperature regulator was purchased along with the heating cable to control the soil temperature more consistently. The cables were designed to keep soil temp at a certain degree above ambient temperature but we wanted the soil temperature at a consistent 70 degrees for our research. A soil temperature thermometer was also purchased to record soil temperatures in the raised and regular beds. A notebook was purchased to record these measurements.

Seed was purchased for planting broccoli, pac choi and Chinese cabbage in the raised and regular beds. Seed was also purchased to test new varieties of greens for their growth rate during mid-winter and be taste tested by CSA members. A log book was purchased to note new planting schedules designed to maximize production during mid-winter. Seeding and germination dates are recorded as well as harvest date. When plants are harvested for CSA shares, an equal number are taken from regular and raised beds. They are each measured for length and the total harvest in each bed type is weighed and recorded. This record system will continue as more crops are harvested through the winter.

The results thus far are not at all what I expected. I assumed that added heat in the soil would result in increased production. I just wasn't sure if that added production would warrant the added cost, energy and effort required.

The first harvest of Chinese cabbage from the raised and regular beds was the same in size and weight. This was not surprising since the soil temperatures were similar-in the high 60's. The second harvest showed that the crop grown in the regular bed was, on average, 1 1/2" taller and weighed twice as much as the crop grown in the raised bed! During this time, the temperature in the regular bed was approximately 15 degrees cooler than found in the raised beds.

I will harvest Chinese cabbage again next week (Jan. 2) to continue monitoring the compared harvests.

I have also noted that the broccoli in the regular beds has started forming heads and those in the raised beds have not. I haven't seem much difference visually between the pac choi in the two bed types. They will begin to be harvested two weeks from now.

Thus far, my changed planting schedule for the greens in the hanging planters shows useful results. I seeded eight rather than six planters each week at the beginning of my season (Sept-Oct) and included with them some of the varieties (mache, red Russian kale and claytonia) that I know are slower growers. This gave me enough greens for the initial harvests and adds the slower growing varieties into the harvest mix when the other varieties are on their second or third cutting (less harvest than the first cutting). This gives a more consistent harvest amount and quality for each planting.

The eight new greens varieties that I planted two weeks ago are ready to be moved to the planter hangers but all the hangers are currently in full production. Next week I will rotate out the harness planters that have their final harvest and move the new planters to those spaces. I will note how quickly each is ready for harvest and how many harvests each produces. I can't pronounce half the names of these greens, as they are Asian varieties, many in the mustard family, but some look close to harvest size already. I look forward to observing their progress.

I will continue to monitor soil temperature and harvest size in the raised and regular beds. Soon, transplants will go in to replace harvested crops and I plan to try a good winter producing fresh-eating turnip, Haukeri, to see how it does comparatively in the warm and cold soils. I will note growth of new greens varieties and conduct a survey with shareholders to find out how they like these varieties. Even though I am most interested in the data collected until the end of February (since my focus was on the toughest growing time; mid-winter), I will continue to monitor the plants until the CSA growing season ends in mid-April.

I am still gathering the data for my research, so I have not done a lot of sharing yet. I did a presentation about my winter CSA business at a Conference on Eco-Ventures (green technology business development) held in Wilmar, MN. In my presentation, I noted that I was doing SARE funded research and described what I was doing. I also taught a session of the "Farm Beginnings" course offered by the Land Stewardship Project. One area I covered was monitoring and I used my SARE research project as an example.

My husband Chuck and I are writing a book about our winter CSA business. It includes a section on production where I will include results from my SARE research. We recently were awarded a $5,000 grant from the West Central Regional Sustainable Development Partnership as seed money for this project.

The University of Minnesota, Morris, produces a gardening show for public television, "Prairie Yard and Garden. Host Sue Gooch and her film crew were at my home last fall to film the late season crops I grow and will return in mid-January to film in the greenhouse. We will talk about how I grow vegetables all winter, and will include my SARE research on productivity.

Chuck and I are also offering a workshop on January 19, 2008 on winter greenhouse construction and production. I will share our SARE research with participants during my presentations on production and they will be able to see what we've done during tours of our greenhouse.

I am going to be on a panel about winter production at the Sustainable Farming Association's annual conference in February. I will be able to discuss my SARE research during that discussion.

This spring, I will give a talk on winter production at the Morris campus with the help of our Sustainability Coordinator, Troy Goodnough. I plan to discuss my SARE research results during that presentation.

Chuck and I are doing consulting work with biology high school teacher Robert Palmer and his Wilmar high school students. As part of their project for the Youth Energy Summit, these students want to raise winter produce they can donate to their local food shelf. Chuck is helping them retrofit an existing greenhouse and I have just begun meeting with them to discuss production. They will be able to benefit from my SARE research findings as they begin their own experiments in cold season production.

I'd like to add that I am very grateful that SARE has given me this opportunity to explore improved winter production. One of the goals of Garden Goddess Produce is to encourage others who are interested in exploring the possibilities of growing vegetables in winter in the upper Midwest. While we were fairly confident that we chose passive solar components to our design that would provide maximum return on effort and expense, it is important to be able to back up our claims with research and experimentation. This grant has enabled me to improve my knowledge of the crop varieties I am familiar with and to test out new ones so I can share the results with others to improve all our attempts at winter production.

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