Greenhouse
A layer of bubble wrap fixed over the glass inside is the best way of keeping the heat in. It can be reused for several years before degrading. It's usually supplied in rolls and is easily fixed in place with clips that slide into metal greenhouse frames. If you're reusing old bubble wrap give it a wipe down before putting it up. *Garden tips supplied by <a href="http://www.amateurgardening.com" target="_blank">Amateur Gardening Magazine</a>. ;