Green House

I saw this little 6' X 2.5' X 3' tall, vinal greenhouse for winter growing of small to medium foliage. I was wondering if anybody ever used something like this before and if you had any success. we get below freezing in central florida only a few nights out of the year. I dont have a heat source but I hear that plants especially cannabis give off heat. so I thought that maybe they could keep themselves warm in a windless but perhaps a chilly night. I think I would probally be better off just waiting till it gets warm but I like to experiment. Any tips or suggestions?

A vinyl or plastic covered greenhouse is a big heat loser unless you have them double wrapped and/or a heat source inside.

Something that might work better for you is a cold frame.

Seedlings and young plants are transplanted after the last threat of frost. If the growing season in your area is less than five months, you may want to start the plants indoors, or in cold frames, transplanting when the weather permits. A 10-by-four foot cold frame can easily hold 60 two-month-old plants. The cold frame can be constructed with two-by-two's or branches gathered at the site. Cover the frame with a double layer of six- or eight-mil polyethylene plastic or similar material. Attach the plastic to the frame with tacks or staple-gun tacks. If the area is unprotected from the elements, slant the roof so that rain will run off. If the area is windy, place rocks or branches along the frame to add weight. Orient the cold frame to face the south.