Alberto, when I read "insulation" my first thought was insulation against heat. But as I read on, I realize that you mean insulation to retain heat. I've cooked many a plant by trying to grow it in a black plastic pot in full sun. What are some good techniques for keeping pots in full sun from getting too hot? Jim McKenney Montgomery County, Maryland, USA, USDA zone 7, which today means temperatures well up into the 90s F.