MISA/RSDP Local Foods Initiative Internship
Final Report

by Jennifer Adams
May 15, 2004

Introduction

Purpose

Methods

Results

Farmer Input

Techniques

Crops

Hoophouse Guilds

Season Extension Challenges

Costs

Markets

Conclusion/Discussion

Bibliography

Appendices

Permaculture Design Concepts (Appendix 1)

Questions Sent to Farmers (Appendix 2)

Guild Plant Ecological Functions/Definitions (Appendix 3)

Guild Plant Human Uses/Definitions (Appendix 4)

Acknowledgements

Introduction

Growing, purchasing, and marketing local foods have recently become hot topics within the sustainable agriculture community, and even among the agricultural community at large. Local foods systems benefit local communities socially and economically, building an infrastructure that creates and maintains jobs and wealth within local communities (Meter & Rosales, 2001). Advocates of local foods tout the freshness, high quality, and high nutritive content these foods offer eaters. Additionally, many people have awakened to the local foods campaign as a result of increasing energy prices and concerns about the overall environmental, social, and political costs associated with obtaining fossil fuels. Recent national and local efforts to promote the benefits of local foods include USDA's Community Food Security Initiative, LocalHarvest's online farm directory, Regional Sustainable Development Partnerships' Southeast Minnesota Food Network, and Land Stewardship Project's Food & Farm Connection Stewardship Food Network.

Minnesota farmers face difficult challenges competing for markets at the local level, as they operate within an increasingly global food production and marketing system. Small- to medium-sized farms must determine how they can establish and maintain a strong and sustainable presence in local foods markets. Many farmers have adopted innovative production techniques while creating successful marketing venues. This combination has allowed them to remain on the land, strengthening their farms and their communities (Meter & Rosales, 2001).

Compared with other agricultural regions throughout the world, Minnesota growers experience the added challenge of working within a limited growing season. The winter months of "non-production" often exclude farmers from participating in established local markets. However, when farmers are able to lengthen their growing season—both by harvesting certain crops earlier in the season and by continuing to harvest later in the fall—they supply local communities fresher, more desirable food for a longer period of time, retaining their foothold in local food markets (Bachmann & Earles , 2000; Coleman, 1995). Season extension not only provides local foods longer to Minnesota eaters, it helps farmers obtain a marketing advantage with restaurants and stores, as farmers are able to offer buyers local foods earlier in the season and command premium prices, while spreading out farm cash flow. Additionally, the benefits of season extension reach beyond the individual farmer; the multiplicative effect of local dollars spent on locally-produced food strengthens the overall local economy.

Purpose

The overall purpose of this project was to gain a more complete understanding of the possibilities season extension offers Minnesota farmers, focusing specifically on growing techniques (including the use of season-extending structures, tools, and practices), crops, costs, and markets. It is my hope that the information presented here will be useful to growers and others interested in learning why certain season extension techniques are chosen, and how they are combined to increase market opportunities and income for Minnesota growers. I have not included an in-depth analysis of costs and markets, although this type of study would be useful, according to some of the farmers I spoke with. Instead, costs and markets are covered more generally in this report.

The crops section of this report includes two Hoophouse Guilds created for growing cold-hardy greens in Minnesota . The guilds are based on edible greens planting guidelines developed by author and organic grower Eliot Coleman and Dr. John Biernbaum ( Michigan State University), which have been expanded upon by adding perennials, and applying companion planting and permaculture design concepts. These guilds are offered as an example of how a variety of plants can be grown together within a hoophouse to produce greens for early spring harvesting.

Methods

Throughout the semester, I read and referred to a variety of books, reports, and publications relating to season extension (see Bibliography). These sources were helpful in establishing a basic understanding of many of the techniques and tools used to extend the growing and harvesting seasons. I also attended the " Hoophouses for Year-Round Local Food Farming" conference conducted by Dr. Biernbaum at Michigan State University in early March. Dr. Biernbaum has five years of experience researching year-round local food farming using hoophouses . The workshop included visiting two farms--one local CSA (Giving Tree Farm managed by Susan Houghton) that uses 5 hoophouses of various design and function, and the MSU student farm (also operating as a CSA) which uses 4 hoophouses plus greenhouse space to start transplants and produce food for distribution. Steve Moore, a farmer from Pennsylvania , also presented info about his hoophouse farming operation.

In addition, I worked throughout the semester with Paula Westmoreland at the Institute for Agriculture and Trade Policy (IATP), using a searchable Plant Community Database of over 1000 plants (including edibles, medicinals , forages, and cover crops) to create two Hoophouse Guilds. The database contains information on the growth characteristics (including zone, hardiness, and drought/flood/frost resistance information), ecological functions (such as nitrogen fixation, erosion control, nutrient accumulation and flood management), and human uses associated with each plant.

In designing the guilds, we started with some of the cold tolerant greens and lettuces developed and tested by Dr. Biernbaum . (See Results: Crops section.) We then used the Plant Community Database to help identify plants that are 'companions' to these greens, by offering insect/disease protection, added nutrients, and attracting beneficial insects. We used permaculture design concepts (see p. A-1) in creating these guilds, including some perennial native plants--Wild Lupine ( Lupinus perennis ), Sweet Vetch ( Hedysarum boreale ) and Junegrass ( Koeleria macrantha )--that help capture, store and cyclenitrogen, while providing some heating and insulating benefits as they are planted along the outer edges of the hoophouse . The resulting Hoophouse Guilds are plant communities whose individual members (plants) have been chosen to produce edible greens in a hoophouse while providing an even greater diversity of plants to meet a wide range of ecological functions and human needs. (See Results: Crops section).

Another component of my research focused on contacting Minnesota farmers who use season extension techniques and asking them a series of questions about their systems, crops, costs, and marketing strategies; I also inquired about any problems they experience when trying to grow food earlier and/or later in the year. After receiving this initial feedback, I visited three growers to see firsthand how their season extension systems worked. (See p.A-2 for questions sent to farmers.)

Results

Farmer Input

I received feedback from 6 of 15 farmers initially contacted; four of the six who responded grow produce for "large-scale" markets (retail food stores, co-ops, wholesalers, restaurants, and CSAs ), and two grow on a "small scale" in community and backyard gardens. The farmers come from the Southeast and South Central regions of Minnesota , as well as from the Twin Cities and surrounding communities, and they are all either Certified Organic or using entirely organic practices. While I had hoped to receive input from more farmers, I soon realized that the farmers who did reply were enthusiastic and forthcoming in offering information, and that they might be open to having me visit their farms and see firsthand how these systems worked. Therefore, an opportunity emerged to really focus on a few farms and learn in detail about their particular season extension systems and why they chose the systems they use.

By contacting these six farmers, I was able to visit 2 large-scale rural farms, and one of the urban gardens. I also spoke with a third large-scale rural farmer over the phone. Through these visits and conversations, I was really able to get a deeper understanding of how all of the season extension techniques used by each farmer fit into the "whole-season plan," and how each technique opens up another growing window that varies slightly from the other techniques. In this way, I learned how growers try to create a 'seamless transition' from greenhouse/ hoophouse to field, overlapping harvests to ensure a greater level of productivity throughout the extended season.

It was helpful to have attended the Michigan hoophouse conference before I visited the farmers in Minnesota , for a few reasons. First, because I learned so much about the mechanics, construction, purposes, and growing processes of hoophouses , when I came back to Minnesota and started talking with farmers I was able to ask knowledgeable and relevant questions about their systems. Additionally, because Michigan 's climate and plant hardiness zone differ from ours ( Michigan is mainly Zone 5), I was able to form some questions around the possibilities and drawbacks of year-round growing for Minnesota farmers, and focus my research accordingly by looking critically at the climatic differences between Minnesota and Michigan .

Techniques

While Minnesota's growing season is limited in terms of low temperature, early frosts and long-term snow cover in relation to other agricultural regions, this region has enough daylight (in terms of both daylength and light intensity) to grow hardy crops as early as March and as late as November. Some farmers in the southern part of the state have grown greens in unheated hoophouses throughout the winter. This is possible because winter vegetable production relies more on daylength and light intensity than temperature, and geographical latitude determines how much light is available to a particular region at given times throughout the year (Coleman, 1992 &1999). Situated between the 43rd and the 49th parallel, some areas of Minnesota share the same geographical latitude as the Bordeaux wine-making region of France; however, we do not share their Mediterranean climate—most of France benefits from Zone 8 plant hardiness conditions.

By moderating the effects of our early frosts, cold temperatures and frozen ground, Minnesota farmers are able to grow and harvest crops for a longer period of time than those farmers who do not practice season extension. Season extension techniques work to create microclimates; hoophouses , root cellars, row covers, and mulches are all used to moderate a localized climate and create conditions that meet specific needs, such as heating the soil, warming plant air temperatures, or storing foods in cool conditions throughout the winter, preventing them from freezing.

The following section focuses on the season-extending techniques used by the farmers I talked to. It highlights a few of the tools and practices they use to extend their growing and harvesting capabilities. Often, a variety of tools (referring to the structures and accessories used to extend the season) and growing practices are combined to grow crops earlier in the season and/or to extend harvests later into the fall. (See Table 1.)

Table 1. Season Extension Techniques Used by Minnesota Farmers

Greenhouses are generally permanent, heated structures used to start transplants in flats, while hoophouses (also called high tunnels) are usually either permanent or temporary unheated structures used to grow crops in the ground a few weeks earlier than they can be grown in the field. Both are typically covered by one or two layers of UV-resistant plastic supported by "hoops" made of bent steel or PVC pipe. The plants grown inside greenhouses are usually watered by sprinklers or hand-held sprayers, while hoophouse plants are often irrigated using drip tape. Some houses are designed so that the side walls roll up, to allow for cross ventilation at plant-level. Other structures are vented through doors in the end walls (which vary in size), and are sometimes supplemented by large fans or blowers to help circulate air.

Temporary hoophouses can help farmers address nutrient and disease issues by rotating the location of the hoops annually. One farmer I visited uses an extensive 4-year crop rotation and manure application to help build organic matter in his sandy loam soils, and moves his hoophouses each year, utilizing the nutrient rich soil he creates with cover crops. It takes about one day to put the hoophouses up in the spring, and another day to take them down in the fall, to store them over the winter. For his crop rotation, he plants marketable legumes and a combination of cover crops and green manures including oats, clover, rye and hairy vetch over the course of one season, harvesting cover crop seeds for use in subsequent years. The following season, this field is left to grow clover and vetch. A green manure crop of soybeans and sorghum are planted the next year, and are cultivated and treated like row crops. In the fall these are planted over with rye and vetch. In the following year, this field is planted in vegetables. Each year he chooses a section within one of these nutrient rich, cover-crop amended fields to set up temporary hoophouses .

This farmer markets mostly to Twin Cities restaurants, producing transplants in the greenhouse and using his seasonal, temporary hoophouses to grow early crops of tomatoes and melons. The tomatoes and melons are typically transplanted into the hoophouses mid-April, where they grow protected from wind, cold nights and inclement weather. The plastic is removed from the hoop structure just as the tomatoes ripen, when outdoor conditions are suitable for field growth. While only two-percent of this farmer's tomatoes are grown in the hoops (regular field harvest immediately follows the early hoop harvest), this early small crop helps him establish marketing relationships with local restaurants and other buyers that will carry him through the season. In this way, season extension is a marketing tool for him.

In addition to starting transplants in greenhouses, some farmers use cold frames and/or seed beds . Eliot Coleman calls the cold frame the "simplest, most flexible, and most successful low-tech tool for modifying the garden climate" (Coleman, 1992 & 1999). Cold frames can be any size, and can even be constructed using scrap materials. The basic structure is a bottomless box, with sides made from wood planks and covered with glass (often old windows). Seed beds are simply field spaces planted in beds rather than in long rows. For example, one farmer using seed beds sows 20 seeds per square foot, eventually spacing plants 6 inches apart. She said that starting plants in seed beds produces stronger transplants, makes watering easier, and costs less than starting plants in the greenhouse. Whether produced in greenhouses or seedbeds, this farmer emphasizes the importance of using transplants with strong root systems that are not coiled and root-bound. A strong, unbound root system ensures that after transplanting, the plant spends its energy putting on growth in the field, instead of sitting in the soil for a week unwinding its roots. This farmer also uses a cold frame with 12" high sides to harden off transplants before putting them into the field. The high sides of these frames offer the tender plants wind protection as they acclimate to outdoor conditions.

Plastic mulches are frequently used to raise soil and air temperatures, suppress weeds, conserve soil moisture, increase crop yields, and deter insect pests. Many types of plastic mulches are available, including black, embossed (to fit the plastic tightly to the bed), clear (which heats the soil better than black plastic, but allows weeds to grow), infrared-transmitting (IR), selective reflecting (SR) (which reflects far-red light up into the plant), silver reflective (which confuses some insect pests), and photodegradable film (which breaks down after 90 days exposure to sunlight) (Bachmann & Earles , 2000). Paper and recycled kraft mulches are also available however, none of the farmers I talked with use these. The farmers I talked with have used black and SR plastic mulches to obtain earlier tomato and melon harvests, and silver reflective mulch to deter cucumber beetles.

From the list of season extension practices used by Minnesota farmers, the following example shows how site selection , strong transplants , and seed variety selection are combined to help one farmer plant sweet corn for an early July harvest. This farmer starts corn transplants using an early variety hybrid seed corn. The transplants provide nearly 100% germination and an even growth curve, in addition to beating weed and disease pressures normally experienced with field-seeded corn. The high germination rate saves money due to few wasted seeds. This farm dedicates 14 acres of sandy soil, on a dry "ridge" location to produce early sweet corn. In contrast, this same farmer uses hoophouses to grow 750 tomatoes at a site that experiences a cool, wet, valley microclimate effect, prohibiting growing tomatoes in the field. The fields at this site are used to grow cool weather- and moisture-loving crops such as broccoli and lettuces.

The following list offers examples of combinations of season extension tools and practices used by the farmers I spoke with:

greenhouse +double-poly hoophouse = tomatoes, planted 4/15 and harvested 7/4

greenhouse + site selection + variety selection = early sweet corn, followed by summer sweet corn

greenhouse + cold frame + plastic mulch + row covers = tomatoes, cucumbers, melons harvested ~1 month earlier
greenhouse + temporary hoophouse = tomatoes and melons produced earlier for a competitive advantage

raised beds + sub-soil heat + plastic row covers = spinach in February, (urban zone 4)

hoophouse + variety selection : greens and spinach harvest in spring, (urban zone 4)

Crops

In addition to combining season extension tools and practices, farmers also use a variety of cropping systems to use field space and growing time efficiently. Some of these systems include: succession planting, interplanting , companion planting, cover cropping, relay/staggered cropping, and continuous/mid-season planting. Farmers select from cool and warm season crops, as well as non-bolting and early varieties to obtain a longer harvest of a particular crop. (See Table 2.)

Table 2. Combining Cropping Systems and Crop Selection

Some examples of combining cropping systems and crop selection include continuous cropping of non-bolting varieties planted throughout the season (such as weekly plantings of radishes and greens), and succession planting starting with an early variety of one crop, followed by a 'warm season' variety of the same crop, followed finally by a different cool season crop planted mid-summer , intended for fall harvest (two crops of corn followed by fall spinach/greens is one example.)

Hoophouse Guilds

Using permaculture design principles and guided by Eliot Coleman's and Dr. Biernbaum's hoophouse vegetable production techniques, Paula and I designed two season extension guilds: the 'Extra-Hardy Hoophouse Greens and Perennial Guild' (for zone 3+) and the 'Hardy Hoophouse Greens and Perennial Guild' (for zone 4+). Tables 3 and 4 (see following pages) list each plant in each guild and specify the functions and/or uses of the plant. (See pp. A-3 and A-4 for Guild Function/Use Definitions.)

At Michigan State University , Dr. Biernbaum and his students have grown a variety of cold tolerant and cold hardy greens year-round in hoophouses. In The Hoophouse Handbook (Biernbaum, ed. Byczynski, 2003) the following plants are listed as "cold-hardy winter salad" crops: arugula, beet greens, chard, Chinese cabbage, claytonia, cress, endive, kale, lettuce, mache, minutina, mizuna, mustard greens, sorrel, spinach, tatsoi, turnip greens, and watercress. Since Dr. Biernbaum's research has focused on hoophouse growing in Zone 5, and Minnesota growers work mainly in Zones 3 and 4, Paula and I selected the hardiest plants from the "cold-hardy winter salad" crops list to create the edible greens component of the guilds. We then used the Plant Community Database to identify perennial and companion plants that complement and support the greens. The perennials and companion plants act as "supportive partners" that help maintain soil ecology, nutrients, and structure, while helping to insulate the inside edges of the hoop structure.

Table 3: Extra-Hardy Hoophouse Greens and Perennial Guild

Table 4: Hoophouse Greens (Hardy) Perennial Guild

The following diagram demonstrates the relationship among different groups of plants represented in each guild. The main function of these guilds is to produce early season edible greens. The native perennials provide and capture nitrogen while attracting beneficial insects and building the soil. The companions serve the greens by suppressing soil diseases and repelling insect pests, and are all also edible and/or medicinal (Plant Community Database, 2004).

The power of these designs becomes apparent when you identify the ecological functions performed by each plant, and then look at the functions the guild performs as a whole. For example, chives perform a variety of functions. Their roots provide erosion control, accumulate nutrients, and build the soil as they decompose. Chives also provide food and are of medicinal value to humans (Plant Community Database, 2004). In terms of insects, chives attract pollinators and repel harmful pests such as aphids and Japanese beetles (Cunningham, 1998). Finally, as a member of the Allium family, it is believed that chives provide general protection to lettuces and members of the cabbage families through a combination of several mechanisms (including pest suppression and physical-spatial interactions) that create positive plant associations (Kuepper & Dodson, 2001). Each guild also performs an even wider variety of functions, which becomes evident when all the plants and their functions are noted. (Refer to Tables 3 and 4.)

These guilds are offered as experimental models which need testing and further refinement. They have been designed with some degree of flexibility, offering growers a range of choices about hoophouse type and plants. For example, because the native plants and perennials are hardy to zone 3, each guild could be planted in zones 3 and above in a temporary seasonal hoop, in which case the plastic and/or whole hoop structure is removed and the plants are exposed throughout the winter, to be covered again in the spring, preparing to transplant lettuces and greens. Another option is to grow the guilds in permanent hoophouses, planting and growing the edible annuals when the hoophouse conditions allow. Every variation will present different cultural demands; for example, a permanently covered hoophouse will likely need a lot of water in the spring (as it will lack winter snow cover and the subsequent moisture due to snowmelt), while the seasonal hoop option will require more effort to warm the soil before planting.

Concerns about the weediness of certain plants, such as catmint, are also addressed with flexible solutions. Weedy plants may be planted within a barrier (such as a deep pot with the bottom removed) or removed from the guild entirely, if the plant's problems outweigh its benefits. Also, weed management is less difficult within the small-scale and contained environment of hoophouses than it is in field environments.

Season Extension Challenges

While the benefits of season extension are real and significant, the structures and planting techniques do pose some challenges. For example, one farmer who has tried using portable hoophouses (made of PVC pipe and covered with polyethylene plastic) has suffered a few breaks and blow-downs in March wind and snow storms. Even in permanent metal pipe hoophouses, maintaining the plastic layer throughout the winter can be difficult, as high winds can lift and bend the entire structure, and heavy snows can puncture and/or collapse the plastic layer. Permanent hoophouses in Minnesota must be cleared of snow throughout the winter to prevent damage of this sort.

Another challenge involves cover crops and getting into fields early in the season. While cover crops provide many benefits to soil structure and soil nutrients, they can slow soil warming in the spring (depending on soil type) and can dry fields out in seasons with little spring rainfall, making early season field planting more difficult. The farmers I spoke with tend to plant later crops in the fields that retain a spring cover crop, and plant early crops in land that is either tilled in March (within a hoophouse, where the ground never freezes and is very dry in March), or later in April and planted both with transplants and seeds of the same (hardy) crop, using a staggered cropping system.

Costs

The costs associated with season extension will vary considerably, depending on each farm's scale and purpose. Different farms will have different needs in terms of structure types, heating, irrigation, mechanization (use of tractors, automatic ventilation systems, etc.), and the ability to re-use materials and the varying lifespans of those materials (i.e. plastics, frames for structures). Moreover, while farmers agree that an in-depth cost-benefit analysis would be valuable to evaluate the benefits of season extension, most feel that season extension systems are highly complex (due, in part, to their farm-specific, individualized nature) and difficult to study. For example, the farmer who uses temporary hoophouses to grow tomatoes and melons spent $500 per hoophouse to build the structures initially (compared with permanent hoophouse initial costs of ~$1000-$5000, depending on size, quality, etc) and spends two days per year setting up and taking down the houses. Since the temporary hoophouses are stored indoors throughout the winter, the plastic on these hoops is exposed for about three months out of the year and will have an overall longer lifespan than the permanent structures whose plastic is exposed all year long.

These temporary hoophouses are also much smaller than the permanent hoophouses used by other farmers; while overall plastic use by the smaller, temporary hoophouses is minimal in comparison to the larger, permanent hoophouses, the growing space and growing time available to farmers using permanent houses is greater than that of the temporary hoophouse user. Therefore, the costs versus returns for each farmer (in terms of plastic) would need to be evaluated separately to determine the net gain due to plastic use/reuse. In considering this example comparison, one can start to understand the complexity involved with evaluating the costs of these systems, and of season extension in general.

Dr. Biernbaum and his students have assessed their production costs and estimated their profitability by first identifying the fixed and variable costs associated with their growing system. Then they used cost-return projection tables developed by David Coltrain and Lewis Jett (Hightunnels.org) to estimate production costs for each crop. To estimate profitability, they asked: "How do you compare the profitability of crops that vary in space requirement, production time and yield?" and made comparisons based on:

-productivity per unit area (lbs/sq ft)

-value ($) per unit (lb) and unit area (sq ft)

-value over area and time ($/sq ft wk)

For their tomato crop, they estimated an income of $0.17 per sq ft week, based on:

-40 lbs/20 sq ft bed

-2 lb/sq ft

-$2/ lb

-$4/ sq ft

-24 weeks crop time

This income estimate for tomatoes compares with a 6 week production of potatoes ($0.17/sq ft week), a 6 week production of baby salad ($0.17/sq ft week) and a 5 week production of head lettuce ($0.17/sq ft week). All of these crops were grown in 20 sq ft beds. By determining the costs involved to build and operate their hoophouses (including materials, equipment, labor, heat, packaging, refrigeration, and fixed and variable costs), they were able to determine how much income they needed to generate per square foot of growing space, in order to make their system profitable. This is one example of how a cost-benefit analysis can be run for hoophouse production. This same method could also be applied to field conditions to determine profitability (Biernbaum et al, 2004).

Another more basic method of determining benefits derived from extending the season involves determining profits for the extended season period by subtracting all costs from all income derived during the time extended crops generated income. This value can then be compared with total growing season income, to determine what percentage of income is generated from using season extension techniques.

In evaluating these cost-benefit analysis techniques, one farmer I spoke with emphasized that a lot of the published research on season extension has come from farmers and growers who have received grant money to establish their season extension systems, or who work from institutions that provide non-farm salaries. He offered this as a reminder (and not as a criticism of farmer-researchers) that growers operating without additional income and/or resources may experience more pressures associated with the risks involved with season extension. It is therefore important to understand that some farmers feel the high economic gains achieved using intense summer production may outweigh and/or limit the need/desire to extend the growing season.

Markets

Many of the markets served by season extended foods are direct-market sales, although the farmers I spoke with market to a diverse clientele. The farmers involved with this project stated they were satisfied with the markets currently available to them, and sell their crops to restaurants, Twin Cities co-ops and other retailers, wholesalers, customers at farmers markets, and member of their CSAs. (One farmer says his markets are split as follows: 40% Chicago wholesalers, 30% Minneapolis wholesalers, 20% to his120-member CSA, 10% Rochester farmers market.)

The farmers I spoke with also emphasized that farmers considering season extension should first research markets available in their regions by identifying market niches that will pay for the extra management required to produce early and late season crops. It is also important to consider how season extension can be used as a marketing tool, as in the case of the farmer who produces a small early crop of tomatoes and melons to establish and cement a loyal relationship with buyers who will stay with him throughout the season.

Conclusion/Discussion

Through reading, talking with Minnesota farmers, and attending the Michigan Hoophouse Conference, I have learned a great deal about most of the types of season extension used by growers in colder climates. I also learned more about the variety of edible plants that we can grow in early spring and late fall. In the future, more research about root cellars and crop storage could be useful, as these techniques help Minnesota farmers market produce throughout the winter, without having to pay a wholesaler to store and sell their fall harvests. Root cellars in particular offer farmers a low-cost, low-energy consumption method of storing crops. Creating value-added products is another area related to season extension that I didn't include in my research, but is important to understand in terms of how it helps farmers bring in more income for a longer period of time.

Ideally, I would have been able to include more input from farmers in the northern regions of the state. I did learn about an early sweet corn production technique used by farmers near Bagley and just south of Duluth (Nennich, 2004). This system uses an early variety of corn started in the greenhouse and transplanted early- to mid-May into the field. The corn is covered with polyethylene row-covers, retaining soil heat and offering slight frost protection. The covers are removed as the corn begins to tassel, resulting in a 2-3 week earlier sweet corn harvest. I also learned about a project involving a group of 14 Central Regional Partnerships Farmers' Markets. This group is currently considering building a biomass and solar energy greenhouse to address the challenges they face in Zone 3 growing conditions. Future studies could focus on getting a better understanding of how the systems and practices used by Zone 3 growers differ from those used in Zone 4, and which systems are most useful for Zone 3 farmers.

While this project has only touched upon the experience of handful of MN farmers, and while I'm sure there are varying opinions among farmers throughout the state, I think I have accurately concluded that year-round growing is not really a priority for most farmers here (although some have been able to do it), but that extending the season with cool weather and high-demand crops (such as greens, sweet corn and tomatoes) is an important and viable way for many farmers to increase their cash flow throughout the season. Overall, most farmers seem to agree that the economics of intense summer production outweigh the extra costs involved with extending the season for too long. How long and in which ways a farmer chooses to extend his/her growing capacity is an individual, highly personal choice. In general, this project demonstrates that season extension seems to benefit diversified farmers, growing at a 'moderate scale' in general terms, and in comparison with all types and sizes/scales of farms.

As local foods interest grows in Minnesota , farmers have an opportunity to capture new markets using season extension techniques. The freshness and appeal of locally grown foods draw customers to restaurants and retailers who offer goods supplied by local farmers. In this way, season extension techniques and practices offer food growers and eaters an opportunity to build regional food systems together, benefiting local economies, sustainable farms, and everyone who eats local food.

Bibliography

References and Sources Cited:

Bachmann, J. and R. Earles. June 2000. Season Extension Techniques for Market Gardeners. Horticulture Technical Notes, ATTRA (Appropriate Technology Transfer for Rural Areas)

Biernbaum, J., S. Houghton, S. Moore and M. Timm-Cook. March 2004. Hoophouses for Year-Round Local Food Farming (Workshop Notebook and Manual) Michigan State University , East Lansing , MI

Byczynski, L. editor. January 2003. The Hoophouse Handbook: Growing Produce and Flowers in Hoophouses and High Tunnels. First Printing. Fairplain Publications, Lawrence , KS

Coleman, Eliot. 1992, 1999. Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long. Revised and Expanded Edition. Chelsea Green Publishing Company, White River Junction, VT

Coleman, Eliot. 1995. The New Organic Grower. A Master's Manual of Tools and Techniques for the Home and Market Gardener. 2nd Edition. Chelsea Green Publishing, Lebanon , NH

Coleman, Eliot. 1998. The Winter Harvest Manual: Farming the Backside of the Calendar. Four Season Farm, Harborside ME

Cunningham, Sally Jean.1998. Great Garden Companions: A Companion Planting System for a Beautiful, Chemical Free Vegetable Garden . Rodale Press, Inc. Emmaus , PA

Farm & Garden: A Sustainable Agriculture and Rural Living Resource Website. "Row Covers and Season Extension" Accessed February 6, 2004 . [www.farm-garden.com/primers/5/row-cover-&season-extension.htm]

Food and Nutrition Information Center (FNIC) Website. Accessed May 12, 2004 . [www.nal.usda.gov/fnic/etext/000061.html]

Henderson, Elizabeth and R. Van En. 1999. Sharing the Harvest: A Guide to Community Supported Agriculture. Chelsea Green Publishing, White River Junction, VT

Hightunnels.org Website. Information for growers about the production practices and profitable use of high tunnels. [www.hightunnels.org/forgrowers.htm]

Kuepper, G. and M. Dodson. July, 2001. Companion Planting: Basic Concepts and Resources. Horticulture Technical Notes, ATTRA (Appropriate Technology Transfer for Rural Areas)

Land Stewardship Project Homepage. Accessed February 2, 2004 . [www.landstewardshipproject.org]

LocalHarvest Homepage. Accessed March 20, 2004 . [www.localharvest.org]

Meter, K. & J. Rosales. March 2001. Finding Food in Farm Country. (Report prepared for the Community Design Center Hiawatha Pantry Project, Regional Sustainable Development Partnerships of Minnesota)

Nennich, T. and D. Hoffbauer. Very Early Sweet Corn Production. Presented at NE Sustainable Farming Association (SFA)Conference, February 2004, Duluth , MN

Plant Community Database. April 2004. Database of plants, their cultural characteristics, functions and uses. Managed by Paula Westmoreland, IATP (Institute for Agriculture and Trade Policy), 2105 First Avenue South , Minneapolis MN 55404 USA

Regional Sustainable Development Partnerships Homepage. Accessed March 26, 2004 . [www.regionalpartnerships.umn.edu]

Sullivan, P. August 2003 . Intercropping Principles and Production Practices
Agronomy Systems Guide, ATTRA (Appropriate Technology Transfer for Rural Areas)

Sustainable Agriculture Network. 1998. Managing Cover Crops Profitably. 2nd Edition. Sustainable Agriculture Publications, Burlington , VT

Sustainable Farming Association Homepage. Accessed February 10, 2004 . [www.sfa-mn.org]

Appendices

Appendix 1 - Permaculture Design Concepts

• Seek to re-create diversity, stability, and resilience of natural ecosystems

• Utilize guilds: plant in communities

• Utilize multiple functions

(Ex: Most plants in guild serve more than one function)

• Reuse and recycle energies in many different forms

(Ex: Cycling of water, heat and nutrients in hoops)

• Use biological and renewable resources

(Ex: Using plants to capture, store and release nutrients; insulate edges of hoophouse)

• Build connections and relationships

(Ex: Companion planting, native plants, perennials and cover crops)

Appendix 2 - Questions sent to Farmers

1) Where do you farm? What are some regional, local, or site specific-challenges you face when considering extending your growing and harvesting season?

2) Which season extension techniques do you use? (check all that apply, adding any that aren't listed)

greenhouse____ hoop house____ cold frame____ root cellar____

row covers (specify type)_________plastic mulch (or other mulch,specify type)_______

others___________________________________________________________________

3a) Please explain how each season extension technique is used, including which crops and/or plants are grown, how the technique extends your growing/harvest season, and how you benefit from this season extension technique. (use more space if necessary)

(For example: "We grow tomato transplants in the greenhouse and plant them into black plastic on May 5th, 2 weeks earlier than the standard planting date, covering the transplants with Remay. By doing this, we are able to harvest and market tomatoes 2 ½ weeks earlier and charge 20% more than usual."

3b) Please describe any succession planting and/or companion planting techniques you are using, including the use of cover crops or trap crops.

4) What are the costs associated with your season extension system? Please include one-time, startup costs as well as any costs of running and maintaining the system. Also, please specify how season extension structures are heated. (i.e. fuel, wood stove, etc.)

(For example: "The greenhouse cost $2000 initially; each year I spend $500 in general maintenance costs and $2000 for propane heat in March/April.)

5a) Where do you market your crops and foods grown using season extension techniques?

5b) Are these the same markets you use all season? If not, how do they differ?

(i.e. different clients, different location, dates, etc.)

5c) Are there enough available markets to sell your season extended foods? If not, which new markets need development?

6a) Have you noticed/experienced any weather changes that you believe are a result of global climate change? (If yes, list any changes that have occurred in the past ___ years.)

6b) How does/can season extension help you regulate the effects of climate change?

7) What are some of the problems/difficulties you have experienced with season extension techniques? Have you tried any systems that simply just did not work?

8) Are you certified organic? If not, do you farm using organic/sustainable practices?

Appendix 3 - Guild Plant Ecological Functions/Definitions

Appendix 4 - Guilt Plant Human Uses/Descriptions

Acknowledgements

Helene Murray, MISA Executive Director

Beth Nelson, MISA Associate Program Director, Information Exchange

Cynthia Pansing, Statewide Coordinator, Regional Partnerships (RSDP)

Kate Seager, MISA Program Associate

Courtney Tchida, Coordinator, Sustainable Agriculture Minor and WUSA

Jack Hedin, Featherstone Fruits and Vegetables

Atina & Martin Diffley, Gardens of Eagan

Greg Reynolds, Riverbend Farm

Chris Blanchard, Rock Spring Farm

Daniel Unger, Macalester Community Garden

Roger Peterson, Minneapolis Urban Farm

Theodora and Arnold Johnson Undergraduate Research Program

Paula Westmoreland, IATP

MISA/RSDP Local Foods Initiative Internship Advisory Committee

Dr. Bud Markhart, Internship Advisor/Sponsor

Dr. Terry Cooper, Major Advisor

Sharon Rezac-Anderson, RSDP Central Region