Growing Winter Crops in Maine

Spring 2011
Toki Oshima drawing
Toki Oshima drawing

The Maine Organic Farmers and Gardeners Association (MOFGA), the University of New Hampshire and UMaine Cooperative Extension organized a meeting of growers at Paul Lorrain’s Sunset Farm Organics in Lyman, Maine, in December 2010 to tour the farm and talk about growing vegetables in winter. About 50 attended the tour and some 30 met afterward for a discussion facilitated by Eric Sideman, MOFGA’s organic crops specialist. Becky Sideman of the University of N.H. took notes for this article.

To Wash or Not to Wash?

Paul Lorrain generally doesn’t wash winter greens. His crops are mostly off the ground, so they’re clean if harvested well; and, as he moves the crop from the harvest to storage to sale bag, he assesses the need for washing. If a crop is dirty when he transfers it to a fresh bag (and spinach is the most likely to be dirty because it grows low to the ground), he double rinses and spins it.

Nancy Steadman doesn’t wash, and Mackenzie May experimented and found that unwashed greens kept longer than washed. Renee Cantarra stops washing when cool weather kicks in.

Because Nate Drummond grows crops in soil, more soil splashes up than if crops were grown in mostly compost. And because his greens are gritty, he needs to wash them. One grower noted that even after spinning greens, some water remains, increasing the weight of the mix.

What Crop Makes the Most Money?

For Eliot Coleman, spinach planted in an unheated hoophouse in mid-September and picked from Thanksgiving through March brings $6/lb. wholesale. He and Barbara Damrosch pick large leaves, leaf by leaf, leaving enough for regrowth. Mesclun might seem valuable, said Damrosch, but labor and heating costs eat up a lot of the profit. Carrots are easily the best of the fresh root crops they grow.

Lisa Turner’s most profitable is ‘Hakurei’ turnips – but she can sell only so many of them.

Lorrain likes to add heat to his house to ensure getting a crop every week. Mesclun is the top money-maker for him; spinach is an add-on. This year people are starting to buy baby Swiss chard on its own.

Ralph Turner said it’s critical to calculate dollars per square foot per unit of time.

Drummond noted that at some point, it’s no longer worth harvesting, because replanting will give a nice, clean crop that you can cut quickly. The earliest in the year that he starts reseeding is the end of January.

Growers’ Favorite Winter Vegetable

Lisa likes the prolific claytonia: You can always make up your weights – i.e., finish filling bags – with it, and it’s fast to harvest.

Drummond likes head lettuce – especially downy mildew-resistant ‘Adriana’ and ‘Carmona.’ Bags of loose greens don’t look attractive at winter markets, he said, but heads of lettuce do, so it’s good to have some on the stand. He harvests head lettuce until Christmas, charging $2 per small head. He plants head lettuce, spinach and chard from plugs, with three seeds per cell in 200s for spinach and chard.

Regarding downy mildew, Lisa said it’s common in spinach. Mark Hutton said it doesn’t overwinter outside in Maine but might in greenhouses.

Becky Sideman noted after the meeting that downy mildews (DM) are caused by water-mold pathogens – in lettuce, by Bremia lactucae; in spinach, by Peronospora farinosa f. sp. spinaciae. DM of lettuce ONLY infects lettuce; DM of spinach ONLY infects spinach. In both, infection happens when you have DM spores AND five to seven hours of nearly 100 percent relative humidity (or leaf wetness). There is disagreement about whether DM resting structures (oospores) can overwinter in greenhouses or high tunnels; or whether DM requires living weedy relatives as hosts to survive when crops are not in the house. Reducing humidity to prevent dew from forming on the leaves reduces spread of the disease. New crops should not be planted near old infected crops, and infected crop debris should be removed from the greenhouse or tunnel.

Resistant varieties are a very good way to control DM; but the resistance genes in lettuce and spinach varieties are race-specific – so the variety must have the specific resistance genes that make it immune to the races you have; otherwise it’s completely susceptible. Varieties that you purchase with the “highest levels” of DM resistance are resistant to the newest strains of DM that are present in the major production regions of these crops. The problem is that we don’t know for sure what races of DM are present in New England.

Rob Wick at UMass confirmed that little is known about DM in the Northeast. He rarely has seen it in lettuce and would like to get samples this winter to confirm it. (Contact: 413-545-1045, [email protected]. Send samples to UMass Plant Diagnostic Lab, 101 University Drive, Suite A7, Amherst, MA 01002 – but contact Wick first to ensure he’s ready to accept them.)

How To Farm in Winter without Burning Out

Coleman and Damrosch used to take summers off. They found that in January and February, once they paid the crew, there was no profit – so taking those months off instead makes sense, unless you need to grow in winter to hold customers. To afford growing in winter, they plant in fall and hold crops for a huge harvest before Christmas, then cut back severely and let crops recover for five weeks after Christmas. They still sell carrots and freshly dug leeks in January, but those pay for labor.

Drummond likes to keep growing crops during winter to retain good employees all year and for multiple years, even if he may not make money – and he can vacation at that time.

Nancy has hired MOFGA apprentices for fall cleanup; their presence energizes her so that she is ready to go again.

Josh Jennings tries to work a little less in summer, and then in winter work “normally” like non-farmers, balancing the workload so that he’s not exhausted in the winter.

Fertility and Rotations

Coleman uses alfalfa meal, which is low in N and in salts.

Lorrain once used unfinished shellfish compost; its high ammonia concentration killed crops.

Regarding crop rotation, Coleman tries to alternate brassicas with non-brassicas but is concerned about growing too many brassicas in a row. When he incorporated bark mulch to favor soil fungi, nothing would grow for the next three months. Will Brinton suggested adding charcoal because it adsorbs toxins.

Coleman called moveable greenhouses “the best reinvented invention”; moving them allows for rotation. Rimol sells rails for moving otherwise stationary houses. Drummond loves the ability to rotate with his Rimol moveable houses, but they need a lot of anchoring and cause a lot of worry in a windy location, preventing sleep on windy nights. He said houses should be designed to withstand the 5-year storm, and it’s best to overbuild. Cantarra has lost multiple stationary houses to wind and is enamored with moveable structures but is unsure about their security. Lorrain had one roll right down the driveway.

Eric Sideman suggested pulling ropes down inside the tunnel and anchoring the inside middle of the tunnel. Lorrain said his houses are very stable because they put concrete around each ground-post hole.

Ralph’s are in clay soils, but use 5-foot ground posts for extra security. Other participants use longer ground posts than typical. Christopher Hahn hammer-drilled holes into ledge and used anchor bolts.

Jennings had one house move a little. He now uses 4,000-foot boat anchors to hold it in place, but prefers Rimol’s system. Coleman had a 4,000-foot boat anchor pull out, on a Harnois house during an East wind. “There are no absolutes in this game. That’s what makes this so much fun!” he said. Ralph added that sharing failures is important so that others avoid costly mistakes.

Lisa said that methods for preventing lightweight greenhouses from overturning differ according to the type of soil involved. She recommended designing for 110-mile-per-hour winds in winter.

Summer-Winter Balance, Planting Dates, Soil Testing

Cantarra can maintain tomatoes until the end of October but wonders if pulling them earlier (to establish fall plantings) makes economic sense. Coleman recommended growing transplants that can be held as long as possible for fall planting. Jan Goranson said to ask whether you’re really going to sell all those green tomatoes. Goranson Farm keeps a reserve house available in case they want to leave tomatoes in at the same time that they want to start winter greens – but they need more space for greens and end up having to pull some tomatoes.

Jennings heard that some growers out West pulled up tomato plants and left them in the greenhouse, since once they reach the breaker stage (i.e., just showing pink color), they’ll keep ripening.

Becky contacted Adam Montri from Michigan State University, who discussed this at the 2009 New England Vegetable and Fruit Conference. He explained that a farmer in Flint tried this once and it worked well. He clipped tomato plant stems at the base around mid-September and hung the plants from the trusses, tying them up with tomato twine, so that he could prep the soil and plant fall crops. He picked the last tomatoes in early November and hauled out and composted the plants before putting the internal covering over the fall-planted crops. “We don’t have a great market for late season tomatoes but they sure tasted good, even if they were a bit mealy,” said Montri.

Regarding intercropping, Coleman has sown lettuce in the fall under cucumbers. The book Greenhouse Tomatoes, Lettuce and Cucumbers (Michigan State University Press, 1979) by Sylvan H. Wittwer and S. Honma discussed spring undersown lettuce in greenhouse cukes and tomatoes, which was done traditionally in the Midwest.

Regarding weed control with intercropping, Coleman said he mulches with 4-inch flakes of semi-composted mulch hay. Mulch hay is a poor source of N, he said, but soil tests currently do not know how to deal with soils that have more than 10 percent organic matter; he believes they need to be revamped.

Eric noted that growers should be using UMaine’s hoophouse soil test package ( for high tunnel soils.

Steve Fulton added that the Cornell Soil Health Test ( measures biological as well as chemical and physical properties. USDA-NRCS offers cost sharing for this test.

Lorrain uses Soil Food Web testing ( for his compost.

Heat or No Heat

Lorrain heats all of his houses to 37 F and calculates that 22 to 27 percent of his sales go toward the cost of that heating. Eric said that comfort is important. “It’s a lot nicer to work in slightly heated houses, vs. using kayaking gloves, etc.” Coleman said that in small farm economics, the important thing is whether you are having fun.

Lorrain’s houses have two layers of poly but he is not yet inflating the space between them with fans. Becky later cited USDA’s Virtual Grower Software ( for comparing costs of heating to different temperatures with different kinds of structures. Growers enter their location, the size and type of greenhouse, costs and type of fuel, etc.

Using this tool, she compared the cost of heating single vs. double-inflated 17- x 96-foot poly houses located in Concord, N.H., using propane at $3.20/gallon and heating to a constant 37 F from September 1 to March 1:

Sep Oct Nov Dec Jan Feb Total
Single poly ($): 19 242 945 2,487 3,305 2,257 = $9,255
Double poly ($): 12 153 592 1,535 2,032 1,374 = $5,698

In this case, it would cost roughly $3,550 less to heat to 37 F a double-poly inflated house over these six months than it would to heat a house covered with a single layer of poly. A double layer of poly that’s not inflated acts almost exactly like a single layer, said Becky, since it doesn’t insulate any better than a single layer.

Dave Tuttle added that plastic lasts much longer if it’s inflated.

Seed Sources and Varieties

Coleman said that Johnny’s is the best; Fedco is also great; and Territorial sends a special winter growing catalog in the summer. Lorrain agreed that Johnny’s is the best and easiest. Nancy noted that Fedco is most economical. (Note that Fedco is a seasonal operation with an online ordering deadline this year of Sept. 30, 2011.) Damrosch also likes Scheepers and Burpee, while others suggested Seeds of Change and High Mowing, especially for organic growers.

Purchasing Inputs Cooperatively

Eric said that Fedco runs Organic Growers Supply and accepts cooperative orders; and Chuck Cox noted that NOFA-NH also does a bulk order. Cantarra recommended ordering with local farmers, adding that many seacoast people buy together from Ideal Compost in Peterborough, N.H., which is as good as Vermont Compost. Coleman likes Vermont Compost Fort Vee best for making soil blocks.

Securing Quick Hoops from Snow Loads

Coleman said that a December windstorm blew the covers off Adam Lemieux’s Quick Hoops trial at Johnny’s, so Lemieux placed 4-foot grade stakes on angles alternating between the hoops, and he threaded rope across the tunnels and wound it around each stake. Another option is to place some Quick Hoops over the low tunnel at regular intervals, but securing with rope is best.


Lorrain harvests by hand, using no tools, and he picks “boutique greens” one leaf at a time.

Damrosch harvests with a little knife.

Coleman said that three people are working on a “mesclun harvester for the small grower” that will clip uniformly like California growers do. It will be available in a year and will sell for less than $300. Lorrain said it will work only for claytonia and mizuna. Coleman said it will harvest many upright crops.

Coleman and Damrosch find that nearly everything but mache regrows after being cut: ‘Bull’s Blood’ beets, ‘Bianca Riccia’ chicory, frilly endive, mizuna, lettuce. In some cases, truncating the leaf affects the attractiveness of mix.

Drummond said that the bigger the harvesting tool, the more uniform your beds have to be. The limiting factors on his farm are the quality and weediness of the stand. Fingers work better for harvesting and prevent sorting later, he added.

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