Outdoor sowing | Indoor sowing | Raising perennial vegetables
Lettuce and onion seedlings
Most vegetables are raised from seed each year. Vegetable seed can be sown indoors in trays, or outside in the open soil, depending on which is most appropriate for the crop and the time of year. Some vegetables are perennial – they do not need to be sown each year. In fact, these are usually purchased as small plants.
Some vegetables are subject to damage by frost and cannot be grown outdoors until the danger of late frost is past – about mid to late May. However, sowing outdoors at that late stage would leave too short a growing season, so these crops should be sown indoors and planted out at the end of May.
This group of tender vegetables includes tomatoes, sweet corn, courgettes, pumpkins, squash, runner beans, celery and peppers. Sowing indoors to extend the season forward can be also used for some of the ordinary vegetables such as cabbage, cauliflower, brussels sprouts, peas, french beans, lettuce and onions to get early crops.
Indoors, in a greenhouse, kitchen window sill or propagator, seeds are sown in trays of seed compost, kept moist and warm until germination occurs. These seedlings are then pricked out into other seed trays, at about 5 centimetres apart each way, or into small individual pots.
The larger seeds of sweet corn, runner beans, french beans and pumpkins can be placed directly in twos into small pots, the better seedling being retained.
Raising perennial vegetables
Although these many kinds can be raised from seed sown indoors or outdoors, they are often purchased as small plants. Since they are perennial, there is no need to sow each year. These vegetables usually occupy the same piece of ground for several years. Many herbs fall into the perennial category, but a few, such as parsley, chervil and dill, need to be sown each year.