Getting more from a cold greenhouse

An unheated greenhouse is not just somewhere to raise tomatoes. It buys roughly a month at each end of the season, and it does it for nothing.

Late autumn

Hardy salads, winter lettuce, land cress and oriental leaves sown in September will crop through the darkest months under glass, where outdoors they would sulk.

Deep winter

Very little grows below about five hours of daylight, so use the quiet weeks for cold stratification: trees, shrubs and alpines sown now and left to the weather will germinate in spring.

Late winter

From February the light returns before the warmth does. Sweet peas, broad beans and the first hardy annuals can all be started in modules, hardened off through March, and planted out well ahead of a direct sowing.