On 22 Feb 2012, at 18:18, Sujit Hart wrote: > I am new with this group. When you mention cold frame, what exactly are you > refering to? It seems all of you have one in your back yard. Essentially a topless, bottomless wooden box covered with glass or transparent or translucent plastic. You wouldn't think so, but even such a simple affair can give a surprising amount of protection from winter cold, thanks to the earth itself acting as a source of heat - not high temperature heat, but heat nonetheless. In addition, a coldframe offers protection from rain, important in winter- rainfall climates like the Pacific Northwest. Covered with a screen in warmer weather, a coldframe can also keep flying pests at bay, notably narciussus flies. Another benefit is that in summer a coldframe keeps the sun off the sides of pots in it and prevents the soil in the pots from overheating. This is why many nurseries corral their potted plants in areas surrouned with low walls of masonry or wood. You can make coldframes of any convenient material, but my experience is that once you have a little experience with them, it's a good idea to draw up a fixed design instead of cobbling them together from whatever is handy. This mostly affects the cover: should it be old windows, or something made to measure. A bulb frame is a little different, usually referring to a masonry raised bed containing pots plunged in sand, but invariably covered with barn cloches or something similar that gives the plants some head room when they flower in early spring (typically). -- Rodger Whitlock Victoria, British Columbia, Canada Z. 7-8, cool Mediterranean climate