First hard freeze for the winter greenhouse - did it survive?

We just had a really hard freeze here in north west Missouri. This morning I went out to the winter greenhouse to inspect it and see how the temperatures inside compared to those outside. Is the heat sink greenhouse working and did it help the plants survive with outside temperatures at 6 degrees F / -14 degrees C? Join me in this video as we go and see.

Typically we do not see temperatures this low until December and January. We were not prepared for this level of cold. Fortunately the heat sink greenhouse still kept the inside almost 20 degrees F warmer than outside. That wasn't enough to keep all our frost sensitive crops alive, but everything that was moderately hardy and hardy are all doing well.

To help the greenhouse survive any future low temperatures like this we have begun getting up our grow boxes to be protected with mini hoop houses. We are bending frames from 1/2 inch PVC that will be covered with greenhouse plastic. We are going to have miniature greenhouses inside our greenhouse. This will hold more heat closer to the plants and help to keep our hardy crops growing through the winter.