Q – I want to grow a lot of my own produce so is it worth getting  a polytunnel or some cloches?

A – Good quality cloches and long polytunnels stuffed with early produce are simply great, you can grow tons of early vegetables, soft fruit and winter salads under cloches and even more in a quality polytunnel.

So is it worth buying one? The answer is probably yes, since growing early crops outside with no protection from the weather is always risky and can lead to disappointment. A plot that is covered and therefore warms up sooner with the aid of cloches or a polytunnel automatically extends your growing season tenfold and also increases the number of different crops that you can grow.

In fact within the warmer polytunnel environment it is quite possible to emulate a more Mediterranean climate and therefore grow more exotic crops. All polytunnels are constructed from a metal framed semi-circular tunnel which is then covered in tough polythene with UV inhibitors. This in fact extends its lifetime but when it gets old and less effective you can easily buy replacement polythene.

A good 90% of daylight is transmitted through polythene cloches and tunnels, the light is then diffused which stops plants from shading one another. As a huge amount of air is trapped by a polytunnel it stays warmer for much longer than a normal greenhouse and in addition there are no extreme fluctuations in temperature during summer.

For a longer growing season with less chance of frost damage bubble insulation (bubble wrap) can be used with great success. If it is removed carefully in the spring it can then be reused the following winter. Possibly the major advantage of buying a polytunnel is that it is cost effective since for the same price as the cost of a small good quality greenhouse you can purchase a polytunnel that is at least four or five times the size of the greenhouse and so you can grow many more crops and have room to experiment with new growing ideas.

Another advantage of a polytunnel is that it is not a permanent structure and therefore can be more easily moved around the garden when required. It is just so much easier to move the polytunnel than it is to remove and replace the soil each year; this is of course an essential job unless you want disease to build up when you grow the same essential crops year in year out. It would however be misleading to say there are no disadvantages of choosing a polytunnel over a greenhouse. For a start they are much more unsightly and they can be quite complicated and tedious to erect unless you have a team of willing helpers.

The other main problem with a polytunnel is that it is very vulnerable to high winds and therefore needs to be located in a sheltered spot or you risk losing it and all of your crops in the event of a severe gale. A polytunnel is also more difficult to ventilate than a greenhouse, thus allowing levels of humidity inside to encourage fungal diseases on your crops. Be warned also that an open polytunnel won’t keep out stray cats, mice, birds and squirrels after your strawberries or even foraging deer that take shine to your crops.

Also once the polythene of a polytunnel is torn you have a problem since no amount of taping and fixing will hold the damaged area together for long. So there you have it – the pros and cons of owning a large protected growing structure that is far from beautiful but in its own way eminently practical.

Do you buy a polytunnel, or a greenhouse, or even both? A greenhouse is always the more expensive option but with proper maintenance can still be standing long after you have given up growing things, whereas a polytunnel is a cheap solution if you are wanting to cover as much ground as possible, for the minimum outlay.