Extending the Growing Season using a Cold Frame

A greenhouse creates a more stable growing environment so that tender seedlings and plants can thrive. A cold frame is basically an extension of your average unheated greenhouse.

Cold frames provide plants and seedlings with protection from the wind, rain and frost. Because frost and snow in particular can wither and kill plants a cold frame is important in acting as a barrier that protects the cold air temperature outside.

Cold frames tend to be unheated, and one of their main uses is to acclimatise and harden plants and seedlings ready for being planted directly outside. Cold frames are also great for over-wintering potted plants.

Its important that your cold frame is sited in the right place; wooden cold frames can deteriorate much quicker in damp, shady spots so if considering one of these a dry bright spot is best. It is best to site any cold frame in an area that gets a fair amount of sunlight, so that the air within the frame has a chance to warm up. Ideally a cold frame should be situated against a wall such as a greenhouse or outbuilding wall, away from the prevailing winds. If your greenhouse or external wall is heated from the inside, this will also add extra warmth to the cold frame. A site with good drainage is also essential to avoid damp, water logging and rot. A combination of poor ventilation and damp site can cause all sorts of problems with disease and fungal infection.

The majority of cold frames are unheated, so its essential to act quickly if temperatures are threatening to cook or freeze your plants. If the temperatures are set to be hot you should make sure that the lid is open so that air can circulate. If youre expecting a cold snap you can always use extra insulation such as fleece, straw or even a blanket to help protect your plants.

A cold frame makes an ideal addition to any keen gardeners garden. If well built, properly sited and maintained a cold frame can extend the growing season by a matter of months.