Methods for growing out of season vegetables
There are several different ways of growing your vegetables out of season. If you are without glass or polythene protection of any kind, you can still have crops with a bit more care. Altering your sowing dates and or choosing the right varieties is important. Lifting dormant biennial or perennial crops and starting them into growth in a shed, garage or spare room will solve the greenhouse problem. You could also, in some cases, leave the plants where they are and cover them with a bucket or box. With the additional help of fermenting, which generates heat naturally, you can get them cropping even earlier.
Growing without glass
Even if you have no protection at all in the form of cloches, frames, tunnels or a greenhouse, there are still quite a few crops which can be had at times other than their normal seasons. You can grow these by manipulating the date of sowing, choosing a sheltered part of the garden and selecting varieties which are either quick-maturing, early, or bred for out-of-season production, which will grow in abnormal conditions of light and temperature.
Broad beans for instance, if sown in late autumn, using the long-pod varieties, will crop the following summer, up to a month earlier than those sown at the more usual time of late winter. You can have them at the end of the season, too, long after the main crop has finished, by sowing in early summer; these will then crop in mid- to late autumn.
Onions are another crop which, although they may store for a very long time, are usually finished by sometime in spring, and it is late summer at least before the new crop is ready. However, by sowing the new Japanese varieties at exactly the right time—this is crucial— in the second week of late summer (varied slightly for north and south), they will be ready for lifting the following early summer.
Other crops you can grow by varying sowing dates and sites, and choosing the right varieties include runner beans,, sprouting , celery, , leek and radish.
If you have a shed or garage which is frost-proof but not heated, you can gently force some crops. Although this may take a couple of months, crops such as, and asparagus should be ready for use in mid to late winter. With the help of box or bucket coverings and rotting leaves, manure or activated straw, they can be brought on more quickly.
Using cloches and tunnels
Even without heat, you can manage a wider choice of vegetables if you have ‘mobile’ protection, such as cloches, frames or tunnels made of plastic or glass. There are four different ways in which these can be used.
You can put the cloches or tunnels in place a week or so in advance of the sowing date, so that thewill warm up, and, if necessary, dry out so that it can be worked to a suitable seed-sowing tilth.
A second method is to advance sowing dates by several weeks in spring, and immediately put on protection after the seed is sown, thus also bringing forward the date of harvesting. The crop can then be brought safely on in its initial stages, with additional protection at night in the form of newspaper or sacking if the weather becomes very cold. This method applies to, Brussels sprouts, carrot, kohlrabi, , and turnip.
Crops can be had in late autumn by sowing in mid to late summer instead of in spring. The sowings are then covered with cloches, frames or tunnels in early autumn, or whenever the temperature begins to fall, and are finished under them. Vegetables which can be treated like this include carrots, Chinese, peas, radish and turnip.
Lastly, crops of some vegetables can be obtained a matter of weeks ahead of their normal time by sowing in the previous early autumn and protecting at once, or sowing outdoors and transplanting to a frame or using other protection later. This applies to, , peas and radish.
Tunnels, but is of course not generally mobile, unless you have built or bought a lightweight, portable one.