Preface: My college career began at the University of Massachusetts in Amherst, where I pursued a major in Sustainable Food and Farming. Agriculture has long been a passion of mine, beginning with a 12″ by 12″ garden plot in high school, and eventually leading to a summer-long apprenticeship program on an organic farm in the White Mountains, learning opportunities at operations around New England through the Worldwide Opportunities on Organic Farms (WWOOF) program, and the Russell Libby Agricultural Scholarship, which I was awarded during my senior year. Though my career focus has shifted to nursing, I still work part-time at a local farm, research agriculture and food systems, and maintain that same tiny garden plot. This piece was written for Sustainable Agriculture, a class I took while at UMass.
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The vision of winter on a New England farm often evokes images of snow-covered barns and fields, of icicles hanging dormant from trees and farmers relaxing indoors by a roaring fire amid howling winds out the window, pouring through seed catalogs and planning earnestly for the day when the soil will once again be ready for planting. It is an image frequently devoid of production, harvesting, and labor, as if the winter is meant to be a time of inactivity and dormancy rather than an opportunity for further yield and profitability. But indeed, that is exactly what the traditional “off-season” of farming in the northeast is: An opportunity. Practices to create season extension allow farmers the chance to increase not only their production, but also their profitability. By using various techniques and practices ranging from strategic no-cost planting methods to costly and advanced greenhouses and high tunnel structures, growers from across New England and beyond can extend their growing season well into and even through the winter.
With an average of 120-180 frost-free days annually, New England’s ideal growing season can last as little as a third of the year (“Gardening”). This is exacerbated in mountainous areas, where the last frost date can occur as late as June. But consumer demand for fresh produce doesn’t cease to exist when growing conditions worsen. Instead, the ability to sell locally grown fruits and vegetables throughout what is traditionally considered the off-season has proven to be a valuable asset for growers in cold climates. One study conducted at farmers’ markets across Michigan found that using practices for season extension (such as high tunnels) had the potential to “contribute to farm viability” as well as meet demand for locally grown food (Connor 257). Furthermore, farmers who are able to sell their products out of season face fewer competition compared to, as described by Daniel MacPhee, the education programs director for the Maine Organic Farmers and Gardeners Association, the “cutthroat” and “oversaturated” summer markets (Fouriezos). As MacPhee points out, “A tomato in June is worth ten times more than a tomato in August or September” (Fouriezos). This fact subsequently allows farmers to successfully market their product at a higher price. Along with increasing profitability, season extension can also reduce pest and disease presence and the heavy investments of time, labor, and money associated with them (Fitzgerald). Other potential benefits include extended employment opportunities and stronger customer retention rates (Roos). Though season extension does introduce the reality of a year-round work schedule and higher production costs (Pool), as a whole, the advantages of implementing these techniques far outweigh any potential difficulties.
It is clear that extending the season has the potential to provide a host of benefits to farms of all sizes, ranging from greater profitability to enhanced pest management. The question now becomes how to implement season extension into one’s operation. As a whole, a wide range of options exist, costing as much or as little in time and dollar value as the farmer wishes. Before putting these various techniques into practice, one must take a number of factors into account, including necessary equipment and technology, new market seasons and options, and price changes. Season extension truly adds a whole new layer to the existing structure of a farm, and it is essential to carefully consider one’s goals and objectives before diving in. Fortunately, there are almost as many options and practices as there are willing farms and farmers.
Among the most popular no-cost season extension techniques are field and variety selection, transplants, and wind breaks. First, strategic field selection can be an effective way to produce a yield at an earlier date. This can be accomplished through utilizing southern-sloping fields early in the season, given that this land warms sooner in the spring (Roos). Additionally, the farm’s microclimates must be considered. Cold air, which is heavier than warm air, naturally settles in flat and low-lying areas (Roos). Thus, planting in higher areas allows tender or fragile crops the best chance of survival when faced with harsh conditions (Fitzgerald). Furthermore, taking advantage of naturally occurring or strategically placed windbreaks, including perennial grasses and hedges, trees, and fences, can effectively reduce wind and the subsequent “wind chill factor” that can cause plants to experience colder conditions (Roos). Proper selection of varieties is another component of early and late season survival. Utilizing cold-tolerant plants, often specified in seed catalogs, as well as starting transplants early, has proven to be an effective method of increasing yield. In fact, utilizing transplants can provide as much as a four week “head start” on the season (Roos). As a whole, there exist a number of season extension techniques that require no extra cost, only a careful consideration to the planning and designing of the season.
For farmers willing and able to invest a small amount of money in equipment and materials for season extension, options such as row covers, mulches, and low tunnels are frequently used techniques. Mulch, or material that covers the soil directly surrounding plants, can come in a variety of different forms (Pool). Among these are black plastic, IRT (infrared-transmitting) plastic, and biodegradable materials. Black plastic, among the most frequently used types of mulch, has the ability to raise soil temperature as much as five degrees (Fitzgerald). IRT plastic increases the temperature even more given that it allows for increased light transmission. Finally, while it is the more expensive option, biodegradable mulches made from plant starches are another option to consider, and are similar to black plastic in terms of soil warming abilities (Fitzgerald). Along with warming the soil, mulch also provides additional benefits such as acting as a weed suppressant and a means of conserving soil moisture. However, it should be noted that straw and newspaper, other frequently used mulches, do not contribute to soil warming. In fact, they actually cause the soil to be cooler than the bare ground (Fitzgerald). Thus, these types of mulches should be used in cases where weed suppression and moisture conservation are the only desired outcomes.
Row covers, light and often permeable fabrics placed over plants, serve to retain heat and protect against frost damage, though they can also provide additional benefits such as wind resistance and pest reduction (Skidmore). In general, two types of row covers exist: Floating row covers, which are placed over one or more crops with no additional support, and hoop-supported row covers, which utilize metal or plastic pipes or tubes to provide lift to the cover. These covers are typically made of polyethylene, polypropylene, or traditional greenhouse plastic (Roos). Row covers with hoop support are also known as low tunnels. With a height of roughly 2-3 feet, they can be manually fitted with small slits or punched holes in their material to allow extreme hot air to escape (Roos). Farmers can also choose to implement higher low tunnels of 6-8 feet above the ground. Frequently referred to as “caterpillar tunnels,” these structures provide many of the same benefits as high tunnels, along with increased portability (Pool). As a whole, though row covers have certainly been found to be beneficial for season extension and frost resistance, it should be noted that one will need to give special consideration to the ventilation and irrigation needs of the plant, given that some row covers are not at all or only somewhat permeable. In larger structures such as caterpillar tunnels, ventilation is often achieved by pushing or rolling up the material along the sides of the tunnel during periods of warmth and sunlight. This strategy can be replicated in smaller, lower structures by removing or rolling back covers when necessary.
Similar to row covers and low tunnels, high tunnels, or hoop houses, are greenhouse-like structures that allow for passive heating (Kaiser). Crops are planted directly into the soil, and, in addition to increased warmth, receive protection from poor weather events such as heavy rainfall. Additionally, high tunnels can be used for more than just season extension. A study from the University of Wisconsin-Madison on tomato varieties found that crops planted and grown in hoop houses “outperformed an adjacent and identically managed field plot by a significant margin,” yielding a “higher marketable yield” as well as “lower disease incidence” (Healy 571). Indeed, the use of high tunnels for crop production can be taken advantage of all year long, during both peak production and the traditional off season.
Within the use of high tunnels, a number of construction options are available. These structures are often mobile, and can be built using a variety of different materials. Plastic PVC pipes (painted with latex paint to eliminate the possibility of plastic degradation) provide a durable and inexpensive option. Wooden baseboards can be installed on the outside of the PVC hoops, as well as at the ends of the tunnel to create endwalls. Metal and steel can also be used for frame construction. After the frame is built, the tunnel is covered with one or two layers of greenhouse-grade polyethylene plastic. One common feature of high tunnels is the ability to roll their sides up and down for increased ventilation, especially during warmer months. This can be accomplished with an additional pipe connected to the plastic and spanning the length of the greenhouse that one can physically rotate to roll the sides up (Kaiser). Additionally, There are two types of tunnel structures that can be constructed, differentiated by the shape of their roofs. The first, Quonset, has a rounded roof that makes a semicircular shape with the ground. These tunnels are usually simpler and less expensive to build, however, a major disadvantage is that they are often inefficient at removing heavy loads of snow and can be prone to collapse as a result. On the other hand, Gothic tunnel structures have straight sides and a peak at the roof. This shape makes snow removal more effective. The height also allows for more growing space on the sides of the hoop house, as well as aids with air circulation (Kaiser). Other considerations in regards to high tunnels include proper site selection and irrigation needs. However, it is clear that, as a whole, high tunnels offer an effective means of season extension for crops ranging from salad greens and root vegetables, to, increasingly so, berries and flowers.
Arguably the most costly and advanced method of season extension is the traditional greenhouse. Similar to high tunnels in terms of their structure and construction materials, greenhouses utilize heating and ventilation systems and, unlike high tunnels, are typically not used to grow a crop from seed to harvest (Grubinger). Instead of being planted directly into the ground, plants are typically started in greenhouses as seeds, where they are housed in tray packs and later transplanted into fields or high tunnels (Grubinger). Implementation of greenhouses requires the careful consideration of a number of factors, including methods for heating, ventilation, and, if necessary, artificial light. Though greenhouses are most frequently used to start seedlings early in the season, they can also be an effective way to grow vegetables and other crops year-round (Habas). With proper consideration to heating, fertilization, planting, and irrigation needs, as well as a knowledge of crop seasonality, a number of crops can be grown and thrive throughout the coldest winter months. One factor of growing crops exclusively in greenhouses is the absence of natural pollinators (Habas). Given that these pollinators won’t be active during the winter (and that they will be largely unable to reach the plants should the greenhouse never be opened in other months), the grower must consider alternative methods to achieve pollination. This can include fans to mimic the wind, or even pollination transfer by hand through the use of cotton buds (Habas). As a whole, properly established greenhouses certainly offer the most reliable means of growing crops successfully when faced with the colder temperatures, frosts, and snow that come with winter in New England. However, they also require the consideration of a number of factors not applicable when discussing other season extension techniques such as artificial means of heating, ventilation, light, and pollination. Additionally, greenhouses are often both costly and energy intensive, and the grower should carefully consider the goals and practices of their farm before beginning the process of greenhouse design and construction.
It is important to note that season extension methods need not always be used alone. Instead, the implementation of multiple methods at once has proven an effective way to maximize crop production potential. In fact, a study funded by the Wyoming Department of Agriculture found that crops including carrots, radishes, pak choi, and spinach were most successfully grown in the winter through the implementation of low tunnels within high tunnels (Shiwakoti). Thus, when considering these various season extension practices, a farmer should not feel limited to choose one singular technique. On the contrary, methods used in conjunction with one another can produce the greatest yield.
Though season extension certainly has the potential to allow one to grow and produce a yield year-round, the reality that this yield will likely be substantially smaller than that of peak production months cannot be overlooked. To combat this, some farms have looked to develop specific niches that capitalize on their businesses’ particular strengths. These niche operations can subsequently be combined with products from other farms to create what has become a growing phenomenon: the winter CSA. Though CSAs, or Community Supported Agriculture, are traditionally reserved for the busier summer months, more and more farms are joining forces to create a year-round supply for their consumers. In western Maine and northern New Hampshire, the Foothill Farm Alliance is one such example of a successful collaborative winter CSA. Composed of five separate businesses, the farms have joined together to offer a weekly share to their over 100 local members (Watters). In Ossipee, New Hampshire, the 10-acre Pork Hill Farm supplies salad greens, kale, chard, and spinach to the share. With a strategy consisting of high tunnels and row covers, farmers Paul Swegel and Katie Doyle Smith have developed a niche with winter greens and are able to capitalize on this strength within the Foothill Farm Alliance’s CSA. The combined CSA has other positive effects. In the words of Geof Hancock, owner of Hancock Family Farm in Casco, Maine, “We are not five farms pooling resources for money, we are one greater whole, with a vested interest in the health of the group” (Watters). Indeed, season extension can yield much more than just additional crops. Truly, it creates unique opportunities for community involvement and collaboration.
The traditional “off-season” of agriculture in New England and other cold-weather climates need not be a period of dormancy and waiting. Instead, thanks to a number of season extension techniques and practices, a grower can extend his or her season throughout the year, subsequently allowing for increased job opportunities, customer retention rates, and profitability. Additionally, these methods can be tailored to the size, goals, and desired cost expenditures of the particular farmer. Season extension is not necessarily a costly or technologically advanced endeavor (though it certainly can be if one wishes), but instead, at its most basic level can be implemented through simple strategic design and crop placement. As a whole, with the length of the New England growing season being as short as it is, any and every grower can benefit significantly from educating themselves on season extension techniques and, ultimately, the practice of year-round production.
Works Cited
