Insulate with bubble wrap - A layer of bubble wrap clipped to the inside of your greenhouse frame will reduce heat loss and block icy winter draughts. Even an unheated greenhouse will benefit from a layer of bubble wrap. Buy purpose made horticultural bubble wrap insulation from garden centres as this is toughened and UV stabilised. When buying greenhouse bubble wrap remember that larger bubbles will let in more light. You can also use greenhouse bubble insulation to wrap your outdoor pots, protecting rootballs from freezing weather, and preventing your favourite pots from cracking.