Types of Cloche for the Vegetable Garden
The value of cloches lies not only in the sunshine they draw and the warmth they generate beneath them, but also in their ability to shield crops from cold winds — particularly in winter and early spring — and give protection against birds. Here we describe the main types available today before going on to look at the use of cloches throughout the year and at the crops that benefit.
Good cloches are not cheap to buy, but their cost should be reckoned against the number of years they can be expected to last and the value of the crops they will protect. When this is done, a row of cloches will be seen to be a very good investment indeed.
The main types
In recent years, glass cloches have lost ground, in terms of popularity, to the newer polythene and plastics models, but glass is still the most durable. At one time, packs of these cloches were on offer, but today it is customary to buy the fittings and glass separately. The obvious disadvantage of this type is that glass breaks, but with care and experience breakages can be kept to the minimum.
The most usual types of glass cloche are the ‘tent’ and the ‘barns’. The first has two sheets of glass 60 x 30cm (24 x 12 in); the low barn has two sheets 60 x 30cm and two sheets 60 x 15cm, and the large barn is made up of four 60 x 30cm sheets. The latter are big enough to protect tomatoes, melons, sweet peppers, cucumbers and aubergines, at least for part of their growth.
Polythene cloches are usually of tent or tunnel design, and need to be firmly anchored so that the wind cannot carry them away. Plastics designs come in many different forms. A useful one is corrugated, bent to a half-circle and secured with hoops pushed into the soil. These cloches can be stacked flat when not in ‘use, so taking up little space.
How to use them
In French, the word ‘cloche’ means ‘bell’, and the earliest cloches were, in fact, bell-shaped. They were used for striking cuttings or for protecting individual plants. Later, the ‘continuous’ cloche was invented, with open ends so that a number of them could be used together to make a row or ‘run’.
Some cloches can still be used individually to protect particular crops such as a newly-planted cucumber or marrow. Single cloches can also be used for raising brassica seedlings. A low barn will take five rows 10cm (4 in) apart, and if the seedlings are thinned to 5cm (2 in) a single cloche will cover about 60 plants.
Whether used singly or as a run, the ends should always be closed with pieces of board or glass to avoid the creation of a wind tunnel. However, an exact fit is not necessarily essential.
Weeding and ventilation
The modern barn cloche has a detachable pane that makes weeding possible without removing the whole cloche; this pane can also be adjusted for ventilation purposes. Where this refinement is not available, ventilation can be given by leaving a slight gap between the cloches.
Watering is not the problem you might expect, being necessary in spring and summer only. To get at plants growing in the centre, the cloche can be removed completely or the ventilating panel taken out, while for side rows watering can be done over the cloche: water runs down the side sections and into the soil, from where it seeps sideways beneath the cloche.
A good method of watering such plants as tomato, cucumber and melon is to sink plant pots about half their depth into the soil, approximately 15cm (6 in) from the plant stem, and then water into the pots.
The need for watering will be less if the ground is prepared well in advance — this should be kept in mind where a sequence of cloche crops is planned. If the soil is dug and manured in autumn or winter, it will retain moisture much better than a hastily-prepared site in spring. Failing this, fork in some good compost or well-moistened peat to the top layer of soil.
Where cloches are to be switched from one crop to another, a lot of effort can be saved if the strips are reasonably close together. Glass barn cloches, in particular, are heavy and moving them from one end of the garden to the other involves time and effort. Careful planning can cut this down.
Unless the weather suddenly becomes very warm, de-cloching of crops should be done gradually. Begin by removing the ventilating pane altogether or spacing the cloches a little farther apart. The next stage is to remove the cloches completely in the daytime, replacing them for one or two nights until the plants have become accustomed to the changed conditions.
With the possible exception of large barns, cloches are not usually required during summer months. Unused cloches should not be left lying about on the garden, for more breakages happen then than when they are in regular use. Those that are easily dismantled should be taken down and stored away. Tent and barn cloches can be stood on end and stacked one inside the other in a vacant corner or alongside a path.
Before using them in the autumn, give the cloches a wash so that the maximum amount of light is available to the protected crops, and to lessen the chances of harbouring pests and diseases.