Early planting is a key way to make the most of edible produce from a greenhouse, the Royal Horticultural Society (RHS) explains.
The organisation notes that leeks and Brussels sprouts can be started off in greenhouses in February and March before being moved outside after they grow to a decent size.
Also, faster-developing crops such as celeriac and celery can be sown in March, as well as French beans, cucumbers and melons – all of which have large seeds that produce substantial, rapidly-growing seedlings.
The RHS recommends covering plants in glasshouses with fleece on frosty nights and providing additional heating as and when deemed necessary.
Moving into April, the organisation explains that larger-seeded plants such as pumpkins, squashes, runner beans and French beans can all be sown, explaining that they should not be started sooner as they could outgrow the space available in the greenhouse before they can be moved outside.
In related news, a Guardian blog recently explained that carrot seeds can be sown when soil temperature reaches seven degrees C.