KC Gardens

Confusion about cold frames

I got a free tomato plant at the garden show a few weeks back and am trying to keep it alive. I'm also trying to grow some from seeds. I have an old window and am thinking of getting a clear plastic tub and covering it with the window to make a cold frame. I want to keep my tomato plants stocky -- cooler temps help keep plants from stretching. So when should I move the plants to my make-shift cold frame? - Wild Child -