Season Extension at Open Farms: 14 Degrees Outside and 60 Degrees Inside

By Ben Penner, Farm Director

After a year of extreme temperatures — extreme snow, extreme rain and extreme heat — it was nice to have a mild fall. Up until recently the weather has been great for extending the growing season. At Open Farms, we’re still going growing nutritious vegetables in our hoop house, also known as a high-tunnel.


I built the hoop house myself from a partially donated previously used hoop house plus some old pipes, and lots of plastic and plywood. A hoop house is similar to a greenhouse with a few big differences. For example, a hoop house is usually powered exclusively by the sun with no additional heat source though some farmers may use supplemental heat to keep the plants alive during especially cold times of the year. In a hoop house plants are grown right in the soil floor of the structure whereas a greenhouse often utilizes a concrete floor.

As I write this the temperature in the hoop house is a balmy 60 degrees even though it is only 14 degrees and snowy outside. The temperature inside the hoop house is conducive to growing “early” green vegetables such as lettuce mix. We have several hundred feet of nourishing kale and salad mix – our third crop of greens this year — getting ready for a harvest in a few weeks. As long as we continue to have sunshine and our nighttime (or daytime) temperature stay above zero, these vegetables should be heading to our kitchen sometime later this month.





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One Response to Season Extension at Open Farms: 14 Degrees Outside and 60 Degrees Inside

  1. Gwenda says:

    It’s great to hear about the hoop house. It is excititng to know that you can continue to grow veggies in the winter in Minnesota! Let’s hope for a mild winter…