Make a Winter Vegetable Garden Work for the CSA

1 / 4
Sunlight provides passive solar heat to warm the snow-covered greenhouse.
2 / 4
Heirloom purple carrots top this farmer’s harvest basket.
3 / 4
An assortment of baby lettuce may be part of a winter CSA offering.
4 / 4
Greenhouse-grown lettuce is often the main attraction of a CSA provided in January or February.

Imagine living in northern Wisconsin where winter temperatures are regularly measured in windchill. By January, one can’t help but dream of warmer weather, a winter vegetable garden and fresh-picked produce. Now, imagine bundling up and jetting across your yard to a 16-by-24-foot shed, throwing open the door and harvesting fresh veggies in a 70-degree greenhouse that costs less than $50 a year to heat.

For organic Elsewhere Farm owner Clare Hintz, this dream is about to become a reality. This fall, while other farmers “up north” are busy pulling their final crops, Clare will be in full-speed-ahead planting mode. This comes after just two years of researching, planning and building a passive solar greenhouse.


Clare first learned about this econom-ically feasible reality when she met Chuck Waibel and Carol Ford. The duo, which started Garden Goddess Enterprises in west-central Minnesota, provides 12 families with a winter CSA (Community Supported Agriculture). Just recently, they released a how-to manual providing the backbone for others interested in a low-cost solution to year-round fresh produce.

“I live in what is often called a food desert,” Carol says. In other words, getting local produce year-round is pretty much impossible. To Carol, this seemed ridiculous given that Minnesota is a huge producer of food. About 10 years ago, she determined that it shouldn’t be this way: “I had been a CSA member for three years and, in that time, I had fallen in love with local foods.” She knew enough about the gardening community to know that there were winter greenhouses in Canada and figured if they could do it, so could she.

Growing vegetables year-round, though, wasn’t enough. “Anyone can grow tomatoes with enough grow lights,” Carol says. “But using a ton of fossil fuels defeats the purpose. We wanted to do something that wasn’t too expensive – something that provided the most bang for the buck, and a lot of produce.” The couple, who live in the town of Milan, also wanted something small and replicable.

Turning to books about passive solar design written in the 1970s, the couple soon had a plan. Within a couple of years, the two had created a solid business plan and a greenhouse that was filling a produce void in their community.

While Carol has the advantage of being a Master Gardener, she says anyone can replicate her vision. “You don’t have to be a Master Gardener to make this work. Sure, that helps, but my goal was accessibility,” she says.

A winter CSA consists of three main seasons. The first is “diminishing.” This tends to run from late September to mid-November and features arugula and mustards. The “solstice” season follows from late November to early January and features Tatsoi and Mizuna such as Chinese cabbage, pak choi and mustard greens. “Expansion,” which runs from mid-January to late March, finishes the winter off and features a lot of mixed leaf lettuces.

All in the foundation

The key piece to a successful winter greenhouse is its foundation, one that exists below the frost line. From there, you place gravel in the pit, add air hoses, then top the gravel with rich soil. Relying on simple, passive solar design components, the air inside the greenhouse warms up and is diverted underground through a pipe. There, the heat is stored in the gravel. A small backup propane furnace ensures temperatures never drop below 40 degrees. Rain gutters suspended from the ceiling create a multitier garden to make maximum use of the space.

As for the price tag, it varies. Carol and Chuck estimate their greenhouse cost about $18,000. This included remodeling the garage to which the greenhouse is attached. In Clare’s case, she anticipates spending about $8,000. While the price difference is a huge spread, there are a number of variables to take into consideration. Regardless, the numbers work out. In Carol and Chuck’s case, they have a waiting list of more than 45 people. And, despite only charging $18 to $20 per week for a share of winter produce, they are making enough of a profit to expand.

Eating local food

In both cases, though, it isn’t about profitability. While sustainability is important, it is more about ensuring people have access to fresh produce. Right now, estimates show that food travels an average 1,500 miles before it gets to your plate. When you factor in how that food was produced and the transportation costs affiliated with production, it is easy to understand the economical benefits of keeping food local. Add in the health benefits, and suddenly a winter CSA starts to make sense.

“Think of it this way,” Clare says. “In the first 24 hours of harvesting vegetables, 50 percent of their nutrients go away. In the store, you might be getting something four or five days after it was harvested, if you’re lucky. In a CSA, you’ve already eaten the food before the stuff in the store even makes it to the shelves.”

One could argue that eating local food is easy for farmers like Clare. Her 40-acre farm currently includes 375 apple trees, 100 cherry trees, 60 pear trees, 50 Korean pine nut trees, 20 walnut trees, an abundance of produce, heritage turkeys and a bee colony. Not bad for a single, part-time farmer who works a full-time day job at a local liberal arts college. She figures if she can do this, anyone can.

“I once lived in Chicago on a small city lot,” she says. “And the thing that’s so great about this greenhouse is we could have done this just as easily in Chicago. All you need is a little yard and some southern exposure.”

The greenhouse plans are designed for an urban farmer. This winter, Clare will test the success of her project, with a goal of serving a dozen or so families in the Chequamegon Bay area. Beyond that, Clare is already dreaming bigger. “If this works on a small scale, there is absolutely no reason I wouldn’t ramp up to have full-size greenhouses in the future,” she says. “If the numbers work out, why not?” Spoken like a fearless woman, dedicated to solving the food dilemma one piece of produce at a time.

For more information

The Northlands Winter Greenhouse Manual: A Unique Low-Tech Solution to Vegetable Production in Cold Climates is available through your local bookstore or by visiting Chuck and Carol’s website: