Brighter future for protected crops

As planning concerns ease a little, polytunnel manufacturers reveal current trends. Mike Beardall reports.

In late 2006, residents in Godalming, Surrey, challenged the right of grower Hall Hunter Partnership to erect polytunnels at Tuesley Farm. Their move was the start of a worrying 12 months for growers increasingly reliant on polytunnels to ensure the viability of their businesses.

The good news is that, while many challenges remain, the tide does appear to be turning to a degree, with a number of important recent cases finding in favour of growing businesses.

In the Hall Hunter case, the Royal Courts of Justice ruled against the firm. But on appeal Hall Hunter was granted permission to retain existing tunnels.

More recently, a landmark decision has allowed Herefordshire grower George Leeds of Withers Fruit Farm, Ledbury, to install tunnels on three agreed zones while following strict guidelines. Soft fruit grower and NFU West Midlands chairman Anthony Snell said the ruling will give Herefordshire growers renewed confidence in the future of their businesses.

Last year, Herefordshire Council dropped a controversial policy to subject existing polytunnels to planning permission in the face of a possible judicial review backed by the NFU and British Summer Fruits. The council is now planning a specific amendment to planning regulations regarding polytunnels in the form of a supplementary guidance document. The council is in discussion with growers across the county as it compiles the document, but in the meantime it is encouraging growers to submit planning applications.

Because there is no national policy and rules vary from one area to another, most growers are trusting their own judgement and working to build bridges with communities and councils.

"There is no consistency between counties and local planning authorities, so it all depends where you are based," says sales director Rob Tasker of polytunnel supplier Crop Pro Tech.

"There are huge variations in councils in the way in which they interpret planning in relation to polytunnels," he adds. "All the Government has said is that councils should take each case and judge it as they see fit."

As Snell points out, the industry has its own code of practice governing the use of polytunnels, which all growers abide by and which could serve as a model for the Government. The code, drawn up by the NFU and British Summer Fruits, includes impact on local communities, distance from roads and houses and all the aspects that planners would take into consideration.

"We have had very little controversy over the past few years - and that is because growers have worked hard to keep local communities and councils informed," says Snell, whose business AJ & CI Snell won the Grower of the Year - Edible category at the Grower of the Year Awards 2008 last month.

Staffordshire-based New Farm Produce, which has 30ha of strawberries and raspberries under polytunnels, is a good example of a business that has worked hard to keep the community informed of developments. Director Stephen McGuffie says: "It is important that all your neighbours know what you are doing and, to this end, we have had open days to explain what we do.

"One of the ways we have tried to make polytunnels more environmentally friendly is to use green plastic on doors and the outside edges of tunnels that can be seen."

Likewise, Snell has tried to meet objections. "We have carefully sited polytunnels so they won't be seen by too many people and have surrounded them with trees. We have also carefully followed our own code of practice to be as responsible as possible."

Ultimately, a spirit of co-operation is essential in the debate over polytunnels, as Snell says: "All growers should have a dialogue with the public and with councils to maintain good relations."

Automated ventilation

Growers with larger-scale polytunnel operations are switching to more automated ventilation systems in a drive for extra efficiency.

The trend has led to an increase in sales of motorised units that can be linked to control systems.

"It's the one area in which we've seen development during an otherwise stagnant period of growth over the past two years," says site manager Stuart Robinson of Lancashire-based Northern Polytunnels, which makes and supplies frames, covers and sundry items.

"Customers have been cautious in spending over the past two to three years, probably because of the weather and increased costs.

"There is less margin for error in ventilation with a control system that senses changes in temperature and alters ventilation accordingly."

Straight sides

National Polytunnels sales manager Gareth Summerfield says the company has seen, in the past year, a 10-20 per cent rise in the sale of straighter sides of its multi-span blocks.

"Because roof ventilation is not cheap, automated vents on the side are easier to achieve in straighter sides," he says. "An increase in height from 1.7m to 3m or even 4m has been created with wider straight-sided polytunnels."

This achieves more air flow through the sides and creates wider spacings in the bays. The "super bay system" works well for those nurseries branching out into retail sales. Rather than developing a new retail building, super bays allow for a flexible option to be put up and used as retail or growing space, depending on demand. Summerfield says: "The great advantage of straighter sides is that for point-of-sale units the side can be lifted for display purposes."

The firm has been offering the system for a few years now and sales remain strong both nationally and abroad.

Stronger tunnels

Sales representative Tim Crossman of Herefordshire-based Haygrove, which pioneered the development of polytunnels in the mid-1990s, says growers are buying stronger tunnels.

He says: "The feeling is that with higher costs and planning issues they are putting up more permanent structures with stronger, thicker steel."

He adds that Haygrove's tightly sealed Solo Series is proving popular for early production.

Polythene film technology

Thermal heat block film, a polythene film technology that has advanced over the past decade, is proving popular with both organic and non-organic growers.

Sales manager Andy Barber of Cleveland-based BPI Agri says its thermal heat block film Luminance THB now accounts for about 40 per cent of sales. "It's been around for about five or six years now and in the past couple of years it has become a successful commercial product."

Thermal heat block films reduce the amount of infrared light - heating rays - that enter polytunnels, reducing the temperature inside.

Barber says: "It reduces the daytime temperature by 1 degsC to 2 degsC by diffusing the light. At night it retains 85 per cent of the daytime temperature, saving on heating costs.

"It makes for a much happier environment for the plants. It's particularly appropriate in the summer months when temperatures are warmer - plants get stressed with too much heat.

"Strawberry growers are using it now, as well as lettuce growers."

Managing director Les Lane of Devon-based XL Horticulture says his firm's light-blocker film SteriLite is a popular option with organic growers, because it prevents Botrytis and mildew.

Light blocking can also help prevent the spread of pests and diseases by blocking out the part of the UV spectrum that bugs use for navigation.

"If you can keep the bugs less active then you have a chance to control some of your contamination," says Lane.

BPI Agri is sponsoring PhD students at Reading and Lancaster universities to look into both UV blocking and UV clear - which lets through more UV from a section of the spectrum that can be more advantageous to crops, enhancing their taste, colouration and fragrance. "We're developing ways to try to control the temperature even more by looking at manipulating the UV light blocking and UV light clear," says Barber.

A tough cover for polytunnels incorporating a new polymer has been introduced by Crop Pro Tech.

Five Seasons Poly Super Tough is said to be totally rip-proof, resistant to sun damage and frost, and available in 150mu, 180mu or 200mu.

Sales director Rob Tasker says the French-produced cover has received much praise from users.

"Because of the polymer in the film it retains its shape when stretched," he says. "It is incredibly tough and can be supplied to fit new tunnels and greenhouses. It is designed to last for five seasons and, for that reason, it is very cost-effective."

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