As one of the most valuable additions to the garden, even a small greenhouse should be used to its full potential. Plan ahead to keep it as full of crops as possible.
Aubergines, cucumbers, French beans, melons, peppers and tomatoes are among the most productive summer vegetable greenhouse crops. You can grow from seed, although a wider range of cultivars of these crops can now be bought as young plants from garden centres to make the best use of your greenhouse in summer.
Get sowing
Cucumbers, French beans and melons have large seeds that produce substantial, quick-growing seedlings so can be sown as late as March in the greenhouse. They are sensitive to cold, and although they can be started off in a heated propagator, they will need somewhere warm to grow on.
If you want to avoid the expense of heating the whole greenhouse, you can start plants off on a windowsill indoors. In April, when the weather gets warmer, move the plants into the greenhouse, covering with fleece on frosty nights, or providing supple-mentary heating as and when needed.
Early starters
While summer crops are getting under way, there is space within your greenhouse for raising young plants destined for the great outdoors. Sow Brussels sprouts and leeks, for example, in February and March to get good-sized plants for setting out later.
Other, quicker-growing plants such as celery and celeriac can be sown in March (as can quick-growing ornamental bedding such as cosmos and zinnia). In April, larger-seeded plants such as French and runner beans, pumpkins and squashes can be sown. Don't start these plants too early, as they may outgrow the frost-free space available in the greenhouse before they can be planted out in early summer.
Into summer
Following this schedule, by the time your summer crops need the greenhouse space, young plants of outdoor crops will be ready for hardening-off in a cold frame or under a double layer of fleece. Plant them into their final positions two weeks later.
Set protected crops out as early as you can into greenhouse borders, pots or growing bags. Some shading will be necessary; it is best to add this gradually as it will reduce growth to an extent. Automatic ventilation ensures plants do not cook on warm days.
After making a heavy investment of time in raising and growing greenhouse plants, make sure there are plenty of canes and string in place to train them. Hang sticky yellow traps to provide early warning of pests. Bio-controls can then be ordered (or increasingly, bought from garden centres) in good time to nip infestations in the bud.
Watering by hand can be tricky to arrange if you are going away, or even if you are at work during the day. Consider investing in an automatic watering system. Do not allow greenhouses to overheat; ensure there is adequate ventilation and damp down if necessary.