Producing produce cold-weather style

The market for vegetables grown by greenhouse producers appears poised to grow as consumer demand for fresh produce continues to climb. But how to sustain such enterprises, in cold-weather climates has been, for the most part, an impractical and near-impossible business challenge.

However, that no longer needs to be the case. Ten years ago, my husband, Chuck Waibel, and I began a professional partnership that led us down a path to partnership efforts with growers that could very well change the way we think about food throughout the United States.

We combined our talents – mine as a horticulturist and Chuck’s as an inventor – to develop a unique passive solar greenhouse designed to produce fresh produce throughout the winter months in northern climates. Little did we know that our combined skills would not only launch our successful winter production business—but also lead to the formation of the Deep Winter Producers Association, an entity comprised of produce growers that share a passion for providing fresh food to local markets.
 

Win-win niche

While growing produce during the winter months in northern climates is a niche market, the reality is that niche markets make money in virtually all businesses. There are niche retailers, niche service providers, niche manufacturers, and when it comes to horticulture, growers with multiple niches have a greater chance for sustained business success while playing a key role in meeting an important market need.

In our case, we saw a market for fresh, local produce in the rural area of west central Minnesota during winter. Our rural county is considered a “food desert” by the USDA because of the distance required for consumers to access fresh vegetables and fruits. That’s ironic, given that we also have some of the richest soil on earth.

We knew we could do better at producing nutritious food for our communities. We also quickly learned that the economic advantage of a local foods system for small towns was a very important piece of keeping communities resilient and attractive to families migrating back into small town America.

But first, we had to create a structure to support the deep winter food production we wanted to try. It also had to be fuel efficient in a tough winter climate. Our structure does that with a design built to capture as much sun power as possible. Here are the basic features of the deep winter greenhouse design:

It is built off the south side of an existing building, to benefit from the wind and weather protection that building offers. In our case, the garage, which was repurposed to be our packing shed on one side, and the garage stall for our delivery vehicle on the other side (separated by an insulated wall).

The south wall of the greenhouse is built at an angle that matches the angle of the sun during the shortest days of winter, to allow as much solar energy as possible to penetrate the double wall polycarbonate panels.

To prevent frost from drawing warmth out of the greenhouse, it has a 4-foot deep, cinder block insulated foundation. Frost rarely manages to sink that deep in our Zone 3 winters.

All passive solar structures include some kind of thermal mass that is warmed by the sun’s energy and radiates that warmth back into the structure when the sun does not shine. We elected to have that thermal mass built below the greenhouse. A rock bed under the structure contains a grid of perforated drainage tile. At the peak of the greenhouse, black stove pipe runs along the length of the building and is connected to PVC pipe that goes down both sides of the structure to connect with the drainage tile below. Fans within the PVC pipe kick in when the greenhouse warms to 70 degrees and pulls hot air above into the rocks below. The added benefit of heating the greenhouse from the bottom up is that the soil is warmed in the process.

A passive solar greenhouse works best as a “cool weather” greenhouse. Ours has a backup propane heater that doesn’t kick in until the air temperature drops below 40 degrees Fahrenheit. This space obviously won’t support heat-loving plants such as tomatoes or cucumbers, but it will produce lovely spring and fall crops, including salad greens, kale, chard, broccoli raab, and Chinese cabbage that customers crave in the the winter months. And as a bonus, cooler greenhouses don’t have as many soil and pest-related problems as do greenhouses at warmer temperatures.

The biggest bonus is low operation costs. The 16- x 22-foot structure uses, on average, $100 a season in propane. That’s right. A season, not a month. That’s saying a lot in a place where subzero night temperatures are the norm, rather than a rarity.

To maximize that precious greenhouse space, we devised a way to double our production area by making planters out of 3½-foot lengths of plastic rain gutter (complete with drilled drainage holes and end caps). They hang in harnesses in tiers of three that run the length of the greenhouse in two rows. In those planters, we grow more than three dozen varieties of salad greens. The salad mix changes with each week and customers love the variety. Even “hot” greens like arugula and mustards stay mild in a cool winter greenhouse.

Our Community Supported Ag (CSA) farm, provides weekly boxes of fresh produce from October to April for “share members” who paid up front for the entire season. Even before production began, we had a waiting list four times the size we could satisfy. Other producers were interested in our success, so to reduce the number of phone calls and emails, we wrote a manual to help others do what we did. As a result, Minnesota and its neighboring states now have more greenhouses built from the concepts we shared. Each is a little different, but all share the basic passive solar features listed above.

It became clear in our tenth year of production that the concept of partnership needed to be taken up a notch. My husband Chuck was awarded a Fellowship from the Bush Foundation to help create an association for deep winter producers. That foundation would explore ways to work collaboratively and support new farmers getting in the game.

Sadly, just as Chuck was beginning his project, he was diagnosed with cancer and died within a month. But Chuck did not want this project to end because he could not carry it forward. While I was coping with my loss, our friends, shareholders, and local food organizations worked with the Bush Foundation to turn Chuck’s fellowship into a memorial grant to be managed by the University of Minnesota’s Regional Sustainable Development Partnership (RSDP). As a result of these efforts, our Southwest RSDP (one of five RSDPs) was awarded the memorial grant in Chuck’s name and I was hired as the project coordinator for that two-year grant. Other regional RSDPs are very interested in the project and the hope is it will go state-wide after this project concludes. 

This is an exciting time for producers, seeking to meet the needs of the rapidly growing niche market of local foods. Our Deep Winter Producers Association will continue to support new growers. Our efforts to grow year-round produce in northern climates can help create a resilient food supply for our neighbors, get more growers in the game, and reduce the amount of fossil fuels required to make it happen.

Carol Ford owns and operates Garden Goddess Produce, a winter CSA in Milan, Minn. She and her late husband, Chuck Waibel, wrote the book “Northland Winter Greenhouse Manual,” which provides detailed information on how to build passive solar greenhouses for growing cool weather crops. She is also a project coordinator for the Southwest Regional Sustainable Development Partnership of the University of Minnesota’s Extension Service. In this role, she is helping to organize the Deep Winter Producers Association to develop ways that members can benefit from cooperative ventures and help winter producers get started. Copies of her book are available. http://bit.ly/1dQI5Am