The Frost Dance

Hot, then cold. Hot, then cold. Repeat for April and the first 10 days of May. It’s been a roller coaster ride for weather so far this spring. Not so much of an issue in the first half of April but once we have our tomatoes and peppers planted in our tunnels we need to take extra precautions to make sure these cold-sensitive crops survive the chilly nights.

You might be surprised to know that in the early morning hours that the inside temperatures of the tunnels basically matches the outside temperature. That’s because the single layer of 4 mil plastic doesn’t have much of anything for R-value. Anytime it gets close to 32* F we worry.

If we know it’s going to be below 32* F we move our trays of not-yet-transplanted peppers, tomatoes, cucumbers, basil & eggplant from our greenhouse to our pack shed. That’s not an option for the tomatoes, peppers and basil already transplanted into our tunnels.

To ensure these cold-sensitive crops survive we use row covers, pictured below, to help trap the heat of the soil under the row cover. We typically see about 3-7* F temperature difference under the row cover which is enough to get us by these chilly nights.

We’re in our 12th season farming and I don’t remember a spring where we had so many frosty nights between April 20 and today. Sure, we expect a 2-3 frosty nights in that time frame but not the 10+ nights and counting.

Tomatoes tucked under row cover for another frosty night.