Winter Production

Fresh local greens in the winter? Can it be?

We've got 'em at Rock Spring Farm, three miles north of Highlandville, Iowa, where we are pioneering the development of a sustainable, organic, four-season vegetable farming system for the Upper Midwest.

While living in Maine, we developed a friendship with market gardening guru Eliot Coleman and became familiar with his system of unheated, mobile greenhouses. We wanted to modify Coleman's system and learn to produce salad greens in the harsher winters of northeast Iowa.

"Walking into Eliot's greenhouses in January felt just like magic," according to Chris. "despite a foot of snow on the ground and temperatures well-below freezing, it smelled and looked just like spring." We promptly set about experimenting with our own winter production during our last winter in Maine.

"When we came back to Iowa in 1999 after a three-year hiatus," Kim says, "we knew we wanted to see if this system would work here." Although we knew that the harsher winter climate in this part of the country would present numerous challenges, we pressed ahead with the construction of three commercial-scale greenhouses. Now, with nearly 6,000 square feet under cover, Rock Spring Farm is working hard to push the vegetable limits in this climate.

The biology behind the project is simply elegant. The salad crops grown in the greenhouse occupy the same ecological niche as many of the woodland wildflowers, which complete their entire life cycle between the time the leaves fall in autumn and the time they reappear in the spring. Rock Spring Farm simply uses crops that have been developed to grow during that time as the basis of their winter salads.

"A number of people have asked me if we're burning a lot of propane this winter," Chris laughs. "I love the looks I get when I tell them we're not burning anything to grow crops in this weather. And with the price of fossil fuels on the rise again, I'm glad we are developing a system that doesn't rely on them."

We grow more than just winter vegetables. Throughout the summer, we use the greenhouses to produce early tomatoes, Dutch glasshouse cucumbers, and sweet potatoes to supplement their additional eight acres of vegetable production. According to Kim, "Some people think we’re crazy. We prefer to think of it as an out-of-the-ordinary passion for vegetables."