I recently set up a small, inexpensive greenhouse (tent and metal pole style, 6x8x8ft peak). It's housing about 10 plants now, and I'm hoping to extend their season (full of ripening pods) and maybe get them through the winter. I have 25 small incandenscent lights on a timer near the roofline. I was thinking about installing some shelves to get the tops of the plants closer to the lights/warmth. But, then again the roots may stay warmer on the floor (made of weed barrier coverered in about 2 inches of dry mulch). What do you think? The shelves would also allow me to get more plants (starts, etc) in there next spring. This is all a big experiment for me. Our winters (Portland area) can vary from relatively mild to 3 weeks of snow and ice, but there's plenty of hard frosts. The first big temp drops are coming up in a few days.