Update on temporary mini greenhouses for two of my satsuma tangerine trees:
I removed the southwest side of the old shipping crate that was placed around the tree that I recently transplanted, and so far has been protecting the young tree from the freezing temperatures, and then I attached some plastic sheet to the 1x4 studs of the crate. You can see the protective film partially pulled back from the plastic sheet. The plastic is so clear, you can't see it.
In the background of the picture above is the 1,550 gal rainwater tank that collects from Shed #2 and the main greenhouse. It currently has about 500 gallons of water in it. The main greenhouse currently houses the blood orange and a few of the Meyers lemon trees.
The picture below shows the satsuma tree inside the crate:
Finally, the view from the open end of the enclosures:
Today is a very pleasant day, with blue skies, an ambient temperature of ~69F. When the temperatures drop below freezing, this south end will be enclosed.
I was concerned the tree in back wasn't getting enough light being enclosed on three sides by wood, so by replacing the southwest side of the crate with plastic, the tree will get more light.
When Spring comes around, and the threat of freezing temps is over, it will be easy to dismantle the enclosures.