Vegetables gathered at just the right time can be stored naturally or, in many cases, by deep freezing, for use months later in the kitchen. Nature, however, makes its own provision for over- winter storage and the survival of the species, which involves either the production of seed (peas, beans, etc.) or roots to remain in the ground to produce seed heads the following season (parsnips, carrots, etc.). Vegetables in this latter group store much better if left in the ground and lifted as required, or stored in clamps.
Root crops should never be stored in plastic bags, for they will invariably rot. If you have well- drained soils, where slugs are not a problem, a winter hardy variety of carrot such as ‘Autumn King’ is best left in the ground; carrots stored in sand or peat often shrivel, rot or go moldy. Parsnips are certainly best left in the row; frost improves the flavor but it is a good idea to lift a few at a time during the winter and leave them on top in case the soil is frozen when they are wanted. Potatoes are frost-sensitive, and lifting at the end of the season for clamping is advisable. Beetroot and celeriac will stand a little amount of frost but clamping is wiser.
For small quantities of vegetables, a mixed clamp is practical, requiring only a limited area of bare ground and a base covering of straw, on which the potatoes, etc., should be heaped, taking care not to bruise. Then cover the heap with a good layer of straw, cone-fashion, with a protruding wisp for ventilation, and bury the clamp under a deep layer of soil. The depth of straw and soil will depend on the likely severity of frost.
Onions and shallots need special care, for they must be mature, with the foliage dried off naturally, usually towards the end of August or early September. After lifting, lay them out to dry in the sunshine, and then string them up as a rope or with the dry tops removed hung in a large mesh net, storing them in a place where there is some air movement and freedom from frost. Fully ripe marrows will keep for several months hung up in open nets in a frost shed. Haricot beans and peas can be harvested ripe and dried for winter use.
Home freezers have brought a simple dimension to storing surplus vegetables, but the secret is always to pick the crops while still in peak condition and to get them into the freezer immediately after harvesting while they are still crisp and fresh. Some vegetable varieties freeze better than others – a quality usually noted on the seed packet.