When to use a coldframe or mini-greenhouse
In spring and early summer, coldframes and mini-greenhouses are a useful place to harden off tender young plants, such as half-hardy annuals and vegetables. These structures can be used to provide a halfway house between the greenhouse and the harsher conditions experienced in the garden.
In late spring and summer, use coldframes and mini-greenhouses to provide extra warmth for tender summer crops, such as aubergine, tomatoes and chillies. This encourages quicker ripening and a larger crop.
These structures can also be used for propagating plants. Try semi-ripe cuttings, raising seedlings, and growing-on young plants.
In autumn they are useful in protecting cuttings and young plants from cooler, unsettled weather and the first frosts (but only mild frosts).
In winter, coldframes and mini-greenhouses can be used to shield alpines from rain and so prevent them from rotting. They can also be used to overwinter young annuals and other plants. A layer of bubble plastic can be installed on the inside to provide some insulation against frost and provide additional draught proofing. However, the bubble plastic will reduce light and ventilation.
Throughout the year, these structures can be used to grow a range of edible crops, and other plants.