Cold frames are ideal for plants seedlings and cuttings that do not need heat, they need to be watched though as temperature can rise quickly if the sun gets on them. Ground level temperature is always a few degrees higher as covered soil will hold the heat. If the frame is against a brick wall the wall will give back heat at night too.
Mine always had a full opening top glass (old windows) that could be propped up in the morning and closed at night. In winter, some bubble wrap or blanket would go on the top weighed down with bricks when frost was due. They do not take the place of a heated greenhouse but are very good for some plants that are not frost hardy but do not need a lot of heat.
A warning always read the seed packet or look it up in a book as some seeds need heat others do not and the heat needed to germinate can vary, it can mean the loss of seed if not heeded.
Last edited: 30 December 2017 10:41:16