Cloches, frames and tunnels: FAQs

I want to make good use of my cloches. Can you suggest a cropping plan?

The most economic way of using cloches is ‘strip cropping’, in which cloches are moved backwards and forwards between two strips of land. (It is easiest, of course, if the strips are adjacent.) Start by sowing dwarf hardy peas or dwarf broad beans under cloches in October or November on Strip A. Leave them cloched until April or early May; then move the cloches on to a summer crop, such as bush tomatoes, peppers, cucumbers, or melons planted on Strip B. In August sow late-autumn lettuce or quick-maturing carrots on Strip A, and cover them with cloches in September, when the summer crop is finished. When these are harvested in late autumn, move the cloches back onto hardy peas or broad beans, this time sown on Strip B.

Have you any general hints on choosing cloches?

The main choice is between glass and plastics. Glass transmits light well and conserves heat better than plastics, especially at night. Its disadvantages are awkwardness in erecting and handling, the risk of glass breakages, and the relatively high cost. Plastics are excellent for protecting plants but they are lighter and easily blown away; so look for cloches which can be anchored securely—either with legs which stick several inches into the soil, or with loops on the roof through which string can be run and attached to stakes at either end of the row. Cloches can rapidly become overheated so some means of ventilation is advisable. If you buy plastic, make sure it has been treated with ultra-violet inhibitors: it lasts much longer than untreated plastic.

I’ve just moved house and in my garden there is an old-fashioned, wooden-sided permanent frame. What can I use it for? I have no greenhouse.

In spring you will find the frame very useful for early crops of lettuce, radish, or carrots, or for raising seedlings. (It may be necessary to stand your seed boxes or pots on other upturned seed boxes, so the young plants are not drawn up towards the light.) In summer a frame is ideal for melons or cucumbers, which can be trained horizontally. Because of the limited amount of light it admits, this type of frame is less suitable than cloches for winter crops, but it can be used for overwintered seedlings of summer cauliflower, lettuces, autumn-sown varieties of onions, and so on, or for forcing chicory or blanching endives.

What are the pros and cons of low plastic tunnels?

These tunnels, consisting of sheets of film stretched over semi-circular hoops about 300-375 mm (12-15 in) high, are the cheapest form of protection for garden crops. They have the mobility of cloches, but are less durable. The film, unless it is treated with ultra-violet inhibitors, lasts only for about one season, although the steel hoops last much longer. Tunnels are easily ventilated, watered, and weeded by pushing up the plastic on one side; but they are less well insulated than cloches—the sides can often be blown upward by winds unless they are anchored in some way. They are, of course, soon outgrown by tall crops; but overall they make a useful substitute for cloches.

I can’t afford a greenhouse. Would you recommend a ‘walk-in’, polythene tunnel for growing vegetables?

Polythene tunnels, widely used in commercial horticulture, are very suitable for vegetables. They are far cheaper than greenhouses, so large patches of ground can be covered. They require no foundations, are quickly erected, and-^-very important—are easily moved to a fresh site when the polythene needs replacing after three years. This prevents the build-up of soil sickness and obviates the need for soil sterilisation, which arises when tomatoes and cucumbers are continually grown in a greenhouse. Use the tunnel for tender crops in summer, and for lettuce, endives, Swiss chard, celery, and winter salads from autumn to spring.