Use of cloches and fleece

The sowing dates of many vegetables and some hardy flowers can be brought forward by two weeks or more by using cloches to warm the soil and protect the seedlings during germination and early growth. Cloches are low transparent covers like miniature greenhouses or polythene tunnels. These days they come in a wide variety of shapes and sizes and can be made of glass or various plastics. Besides warming the soil and offering some protection from late frosts they also keep off certain pests, such as birds and rabbits, and protect plants from wind, hail and excessive rain.

To get full benefit from cloches, the area to be seeded should be prepared and covered about two weeks before sowing. It should also be remembered that the night temperature under a cloche is only a degree or two higher than that outside so that there is a limit to how much earlier you can sow even with this kind of protection.

Cloches should not be left on for longer than they are needed as disease problems can increase as plants become larger and more crowded and they may suffer damage once they start to touch the glass or plastic. Sudden removal should, however, be avoided as this may equally lead to plants being damaged or their growth severely checked. If the design of the cloche allows it, the best plan is to gradually increase ventilation over a 1-2 week period. Plants can then be fully acclimatised to life in the outside world by removing the cloches by day and replacing them at night for several more days.

Fleece is a very light fabric-like material than can be used to protect early sowings in much the same way as cloches. It admits light and, unlike glass or plastic, also lets in rain and air. The levels of weather and pest protection are similar to those provided by cloches and on particularly cold nights plants can be covered with extra layers to give additional protection. Unlike cloches, fleece is easily blown away and needs holding down at the edges with pegs, bricks or lengths of timber but it has the advantage that it can be left in position over some vegetable crops until they are fully mature.

Cloches and fleece are an excellent investment as they have many uses besides allowing the early sowing of seeds outdoors. Amongst other things they can be similarly used to advance planting out dates of seedlings raised under glass. They are also valuable for protecting the early growth of new potatoes and the flowers of strawberries from late frosts, for extending the season of some crops in autumn and to give overwinter protection to autumn sown hardy annuals and vegetables such as lettuce and broad beans.