Just how green are polytunnels?

Farmers claim they cut food miles, reduce pesticides and and give us year-round soft fruits. Others say they disfigure the British countryside. Helen Brown investigates polytunnels

On winter nights, the huge steel hoops whistle, ring and clatter like haunted tuning forks. In summer, they are draped with blindingly reflective polythene. For those country dwellers who live side by side with polytunnels, the rural dream is becoming a bit of a nightmare.

But the growers who have covered the landscape in polytunnels claim that, had it not been for these structures, 1,700 tons of British strawberries would have been lost in the May downpours. They argue that if we want to buy local rather than racking up food miles by importing from Spain, we need the tunnels to extend the UK growing season to 26 weeks (compared with the five- to six-week season we enjoyed 20 years ago).

So should those with a social and environmental conscience buy into, or boycott, the tunnel-ripened berries? And if we accept them, how should they fit into our landscape?

Kathy Smyth lives near Tuesley Farm, near Guildford in Surrey. As a solicitor and an environmentalist, local residents turned to her in early 2004 when Hall Hunter & Partners, which supplies Waitrose, began erecting tunnels on its 470-acre farm. A group of 80 local families formed the Tuesley Farm Campaign, fighting for the tunnels to be subject to proper planning permission. The group's website states that the acres of "hideous" plastic ruins the view and causes flooding.

The campaigners' statement repudiates accusations of nimbyism. They "do not object to the use of large-scale polytunnels in the UK", they say, but "had hoped HHP would behave responsibly and put in a proper planning application, explaining what they intended to do, and where and when they intended to do it. HHP flatly refused to do this."

Smyth asks, "Isn't it right that residents should have a say in profound changes to their local environment? How close to residential areas should they be allowed to come? And shouldn't issues of water run-off be taken more seriously?

"Any polytunnel can end up too close to somebody's house. The National Farmers' Union code says they should be at least 30 metres away from homes. But that's too close. One elderly couple had tunnels within 30 metres of their living room. They stopped sitting in their garden and some days the glare was so intense they had to keep the curtains drawn."

In some areas polytunnels are escaping planning controls because of their "temporary" nature. But if they are up each summer, do they really count as "temporary"? In the case of strawberries Smyth says "temporary" generally means three years, the life of the plant. She says the existing law is clear and recognises that large-scale polytunnels are not temporary and require planning permission.

Which brings us to water run-off. "Anybody living near the tunnels will tell you that run-off increases," says Smyth. "You're introducing huge swathes of impermeable surface. If they had to put in a planning application, run-off would be analysed, just as it is with a car park."

The soft-fruit farmers have made a website of their own. At Tunnelfacts.com they say "Tunnels have nearly eliminated most wet-weather type diseases, reduced pesticide use and enabled success with biological controls and generated huge full-time and seasonal employment. They are 100 per cent recyclable and have created this one-third of a billion pound industry."

Farmers have established a voluntary code of conduct that advises farmers to work with local authorities and residents, keeping everybody informed and reducing the negative impact of the structures. They point out that their main competitors in Spain and California make extensive use of tunnels without having to carry the cost of applying for planning consent.

Anthony Snell, a Herefordshire fruit grower, says that, in addition to reducing food miles, there are environmental benefits associated with polytunnels. "We now use 50 per cent less fungicides compared with open production," he says, "and tunnels create an ideal environment for beneficial insects. We use less water through trickle irrigation.

"We are able to provide controlled amounts of plant food and we get less run-off and erosion. All of our polythene is recycled."

The debate is dizzying. Critics say that flying in pickers from Eastern Europe notches up as many air miles as importing our strawberries. They stress that large quantities of water are required for soft-fruit crops. Farmers point to the money they and East European university students put into local tourism.

Bill Wiggin, MP for Leominster and Shadow Agriculture Minister is refusing to eat Herefordshire strawberries. He told the local press that the polytunnels could cause nearby house prices to drop by 30 per cent. Bill Jackson, who runs the largest estate agents in North Herefordshire says, "We've seen no evidence of this."

Tara Garnett of the Food Climate Research Network says "The University of Hertfordshire has concluded that unprotected strawberry crops use fewer inputs and, with a growing span of two to three years produced lower yields but were more sustainable than polytunnel crops."

The research indicated that the environmental cost of imports from Spain was approximate to that of berries grown here, because Spanish yields are so much higher. But if, as the National Farmers' Union points out, we have a huge storm that wipes out a British crop, all the energy put into its production is wasted. Polytunnels prevent that.

So what does Garnett recommend? "One solution is for people to eat fewer strawberries and maybe grow their own. But we like strawberries, and Spanish imports don't taste as good. Maybe we have to leave the polytunnels alone once the planning permission issues are resolved."

The plastic revolution

* Polytunnels are temporary greenhouses used to grow plants requiring a higher temperature or humidity than that of the surrounding environment. They are made of steel hoops covered in polythene. They have been used since the 1960s, mainly to extend the growing season for soft fruits.

* Polytunnels cover less than 0.01 per cent of all agricultural land, no more than 2,000 acres in the UK

* Sixty five per cent of British soft fruit is covered by tunnels.

* Polytunnels increase class 1 yields by 30-35 per cent.

* An acre of strawberries requires 1,000 gallons of water a day.

* In 2005 sales of British strawberries and raspberries sold through UK supermarkets rose by 17 per cent to £157m.

* The soft fruit industry employs 5,000 full time staff and 50,000 seasonal workers.

* New types of polythene cut temperatures and massively reduce reflective glare.