One year prior to applying for the grant, initial tests were executed in tunnel and hoop house construction and crop production. We were certain we wanted to maintain year-round production of crops in the city and that it should be done within the restraints of minimal budget and using materials readily available to us. The design had to be easily reproducible for other growers to replicate and afford. It had to withstand weather conditions and not diminish crop production in the summer by taking valuable space of its footprint on the site.
By monitoring temperature and growth conditions within the hoop house, which were 6 feet tall, and low tunnels, three feet tall, it was clear that the low tunnels were more affordable, requiring half the plastic poly covering, and less PVC piping, and that the temperatures remained warmer within due to the reduced inside area. A further benefit of the low tunnels was the resistance to high winds and ease by which one could remove snow from them or make simple repairs. Some modifications in design were made for the low tunnels, and an assembly line production of them occurred.
What became apparent to us during the pre-grant trials was the need to hone our understanding of winter season growing. We maintained a log of which tunnels were direct seeded and which had transplants; what temperatures were necessary to maintain a steady production, what crops would survive/thrive in the conditions; how our working hours compared to the profits from our harvest.
We videotaped all steps of tunnel production to make building the low tunnels possible for other individuals or agriculture groups. We also designed a simple flier to further illustrate, in a still photo, some points of emphasis for the builder. To maintain our commitment of education, City Farm received streams of visitors during the course of the year and gave them the tour of the project.
Since its inception City Farm has served as an educational site for local, national and international visitors. For the duration of the SARE grant, there were over 400 K-12 age school children from public and private institutions including on-going seminars with Walter Payton High School and Near North Montessori primary school. Over one hundred college age students visited from a range of disciplines, including local non-profits participating in agricultural programs such as Growing Home and Neighborspace. Also, participating chefs visited to see how product from the low tunnels grows and gave workers feed-back on harvesting and preferences for their kitchens.
City Farm representations went to such venues as the Garfield Conservatory to give workshops on low-tunnel execution and the benefits for the back-yard producer.
Yields from tunnels reaped $3,000 income for the traditionally off-season months of November to February. The November crop came from the September seeding. Per tunnel production averaged, most of the product grown in coldest months was mache, otherwise known as corn salad. The variety is ‘VIT’; seeds are available in most commercial grower’s catalogs. The slow growth the cold produced exceedingly tasty product which chef’s proclaim far superior to the traditional style of growing it hydroponically. Other excellent crop choices are claytonia, which flourishes by March-May, and spinach.
In the coldest months the product growth is nominal. While our interest remains using low tunnels without additional fuel or electricity for heating, steady production is not reliable in Zone 5 climate in January and February.
What became apparent in our study is the necessity to charge a much higher premium for the crop than we originally did. Even with brisk sales (the demand was tremendous in the Chicago setting) the crops are tedious to harvest, requiring a delicate slice at the root level without tearing the root from the soil. With willing customers the price for the off-season product will double in the 2006 season.
Transplanting of heirloom tomatoes was possible one month earlier than in unsheltered conditions which moved harvest time up by three weeks for those varieties. (Variety ‘Tiffen Mennonite’ did particularly well in the tunnel and subsequently in the open air after tunnels were lifted.)
Previously, the City Farm was under the belief that hoop houses or permanent green houses were required for growing in the off-season. These structures are more complicated and more expensive to build and less transportable, thus taking up valuable growing space during the main season. Urban agriculture also faces the reality of urban growth and real estate trends. The turnover of property is a possibility in the near future making a greenhouse a less practical choice.
This grant has introduced to the City Farm, and the urban dwellers that buy produce or come for technical support to the City Farm, the real opportunities for fresh produce to grow sustainably from low-tech, inexpensive structures which can be used for season extension and “off-season” production. The success of this initial investigation proves that a profound yield of winter hardy green could be grown on vacant spaces being converted to urban gardens all over Chicago, profoundly impacting the food infrastructure. Higher yields on spring and autumn crops would be available by covering early spring transplants and protecting autumn crops from the first frost. Community gardeners implemented low tunnels. Back-yard growers and urban agriculture programs will look to adopting this simple means of continuing sales for their projects year round; community and back-yard growers will enjoy the fun of growing greens while the rest of the landscape is covered with snow. The remarkably tasty greens are the proof that these tunnels are the future of local sustainable production.
We were able to identify under what conditions the crops grow best, when to transplant, when to direct seed, what moisture level is required, and how to situate the hoops for better efficiency. We continue to study the ratio of work hours relative to the yield and price point.
I would recommend to other producers to remember the autumn crops in the late summer when it is often the most difficult to focus on the upcoming season. It is crucial to have substantial growth before the hoops are covered with the poly plastic cover, which must also not be so early that temperatures exceed 80 degrees. Build the framework of the hoops well before this busy season if using more than one or two. Choose a day with little wind on which to apply the plastic to the frame to reduce complications in holding the plastic taut. If growing for a market or other sale keep a uniform crop so a bulk harvest will steadily grow; if growing for personal use diversifying the crops will be fun and will let you taste how the cold affects various products.
Resource Center City Farm continues its educational mission through hosting visitors year round to the City Farm, maintaining discussions with the City of Chicago Department of Environment, and working with local school programs. All visitors are taken on a tour of the tunnels, which are a main feature and curiosity piece for the uninformed.
City Farm participated in a Chicago Park District educational program in August of 2005 to report on the low tunnel process and advantages to off-season production. The public was encouraged to visit the site to learn the technique for constructing tunnels and growing crops first hand. Scheduled for April of 2006 is a free seminar where City Farm employee, and key person for the SARE grant, Chris Anderson, will outline the process from start to finish with tunnel construction and planting tips. The DVD will be shown and is scheduled to be added to the Resource Center web site.
To learn precision techniques for growing cold-season crops in unheated structures (hoophouses) for optimal production, nutritional value and price. This project will allow urban agriculture to help fill the tremendous winter demand for cold-season salad greens while engaging inter-city youth in gardening projects.