Polytunnel of true love

The Occasional GardenerEven a small polytunnel is essential if you're serious about growing fruit and vegetables in our climate, writes Sarah Marriot

In June, polythene and aluminium changed my life and now I have to confess to a serious case of tunnel love - polytunnel love, that is. Like a teenager smitten for the first time, I only have eyes for plants grown under plastic.

My old friends, the herbaceous perennials, struggle on forgotten; my teenage crush from spring, the cabbages and potatoes, are fodder for caterpillars; and those new acquaintances, the flowering baskets, hang unwatered.

Polytunnels are often seen as the poor person's glasshouse - and they are far cheaper; I shudder to think what a glasshouse the size of my tunnel (15 feet wide, 26 feet long and seven feet high) would cost. As polytunnels can be so large, they're used more like undercover gardens than glasshouses, so most tunnellers organise raised beds on a rotation system and create paths made of straw or gravel.

Even a small polytunnel is essential if you're serious about growing fruit and vegetables in our climate. Using one extends the summer growing season at both ends, so you can start tender plants at least a month earlier and continue picking lettuce into October. The higher temperatures and longer growing season mean you can easily grow Mediterranean fruit and vegetables, from aubergines and basil to watermelons and grapes.

A tunnel also means you're less of a victim to the weather - in a wet, cold or windy summer, the protection gives everything a better chance of success. But it's not just the plants which benefit. There's no better way to start a day with a coffee in the warmth of the tunnel and few more relaxing ways to end it than by sipping wine while watching your tomatoes glow in the sun.

But sitting around in the tunnel isn't wasted time either; you have to monitor growth, think about the next jobs to do, or just appreciate the almost tropical humidity and lushness.

Putting up a tunnel is easier than a glasshouse; you don't need level ground or concrete and there are no panes of glass to break. The first step is to put the frame together; aluminium hoops slide into the ground and slot into a central overhead ridge bar. Unless you're a DIY whiz, doors and frames are a bit trickier and it might be better to order ready-made ones from the tunnel company. The most labour-intensive stage of erection is digging a trench along the frame, about a foot outside the tunnel area, for the polythene to be buried in.

What I thought would be the hardest part, putting on the polythene, was the easiest. Two of us got the huge sheet over the frame and buried in the trench without difficulty. Despite having to wait through most of June for a day that was dry and still enough to put on the polythene, I hadn't managed to prepare the ground and get rid of all the couch grass, rushes and weeds. Even now, not all my tunnel is planted; some beds have been manured and then hidden by plastic groundcover which will kill the weeds.

My tunnel dreams and plans for the future are like those first stages of falling in love - when everything is possible and nothing is beyond reach.

This column appears fortnightly