December 18, 2016
Challenging Cold
By Derek McGeehan

Some good news: we think most of our crops survived the first round of deep freeze. Another round is settling in now but at least the sun is shining to temporarily warm the plants and air space inside the protective fabric and structures. It's not supposed to be as cold as it was last week but may not rise above freezing today or tomorrow. We were quite nervous early last week as we tried to determine the best way to ensure our fresh crops survived. Trial by error, experimentation, data collection, and research led us to use two layers of our lightweight fabric row cover on top of large interior hoops to protect the crops in the high tunnel. This is where the majority of our greens will come from over the next two months. The picture above shows the interior of the high tunnel and the photograph below shows the healthy green crops that survived under the two sheets of cover. When it was 9 degrees outside on Friday morning the interior of the high tunnel was 12 degrees, cold enough to have killed the crops. Under the 2 layers of fabric, amazingly, the temperature was a steamy 27 degrees, cold enough to freeze the crops but not cold enough to kill them or damage them. No additional heat was added. The crops survived because warm air was trapped under the covers, radiating off the earth.

Before the deep cold we finished harvesting the first round of cutting of baby chard, lettuce mix, and spinach from the hoop house. In there we erected hoops and covered with one layer of fabric in hopes of regrowth and another cutting in a month or so. Those crops appear to have survived. For added security and insurance, we turned on the propane heat in our greenhouse and set the thermostat to 34 degrees. During the 2nd night of deep cold, when the outside low was 9 degrees, a gust of wind blew out the pilot so upon early morning inspection there was no heat in the greenhouse and the air temperature inside was 20 degrees. Disaster? Plants were thoroughly frozen but thawed in a few hours and as of today still seem to have survived.

In summary, we can continue to enjoy fresh organic greens this winter. Happy Solstice!