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Poly-Tunnels and Cloches

How To Use Garden Poly-Tunnels and Cloches
Digging and incorporating as much organic material as possible is the first step - this gives the soil the best chance of absorbing and retaining warmth. Do this before the cloche is put in position.


Put the poly-tunnel / cloches in place a month before sowing. This enables the soil to retain heat in advance of sowing. Water the soil by hand, because the poly-tunnel / cloche will prevent rain reaching the soil. The ideal way to water is to place a length of perforated hose (available from garden centres) along the soil under the cloche. Watering is then just a matter of connecting to the water supply and turning on the tap. 


Sow when the temperature of the soil reaches at least 7C (45F), almost all seeds will fail to germinate below this temperature. When using poly-tunnels or cloches, this temperature normally occurs three to four weeks before the last frost date in your area.

A further advantage can be gained by sowing indoors in pots about five weeks before the last frost date. When the seedlings emerge, they can be planted out under poly-tunnel / cloche protection about two weeks before the last frost is due.

Position cloches in a sunny position and keep the cloches together in units. Prepare the soil before putting the cloches in position and keep the soil as level as possible. Cloches are liable to damage in heavy wind conditions and a level soil will help keep the entire cloche in contact with ground and draught-free.

If at all possible, position the cloches so that they have the protection of a windbreak such as a wall or a hedge. But be sure that the windbreak will not cast a shadow over the cloches. Additionally, the soil around hedges will be less fertile than normal so place the cloches at least 3 m (10 foot) away from hedges.

In general, windbreaks are effective up to a distance of 10 times the height of the windbreak. So for example a hedge 1 m (3 foot) high will provide protection from wind for a distance of up to 10 m (30 foot) from the windbreak. This gives plenty of scope to place the cloches far enough away from a hedge so that soil fertility is not effected but wind protection is effective.

Watering of vegetables protected by a cloche is often considered a problem but rainwater will run off the sides of the cloche keeping the soil inside the cloche moist. In warm conditions it will be necessary to remove one of the top panel of the cloche to enable watering manually with a hose (if permitted) or a watering can. Removal of a top panel will also be necessary in warm conditions to allow air to circulate freely and prevent the build up of disease.

At the end of each season the cloches can be cleaned by simply washing in water and a little washing up liquid. This will remove any algae that has built up.

With very little planning it is easily possible to use the same cloches for three or four different crops in the same season. Click on the link to the next page below for in depth help on how to get the very best from your cloches.