How to secure a Polytunnel in a Windy Area?

Polytunnels are fantastic for extending the growing season, providing shelter for plants, and creating a controlled environment for gardening. However, in windy areas, they can be vulnerable to damage, especially if not properly secured. High winds can tear the polythene cover, dislodge frames, or even blow the entire structure away. Securing your polytunnel against strong winds is crucial to its longevity and effectiveness. This article explores practical ideas and tips for keeping your polytunnel safe in a windy environment.

1. Choose a Suitable Location

Before setting up your polytunnel, carefully consider its location. The right site can make a significant difference in reducing wind exposure.

• Natural Windbreaks:
  Position your polytunnel near natural windbreaks such as hedges, trees, or buildings. These features help buffer the wind and reduce its force on the structure. However, ensure there’s enough distance between the polytunnel and any trees to avoid shading and falling branches.
• Slope Considerations:
  Avoid placing your polytunnel at the top of a hill or in an exposed, flat area where wind is likely to be strongest. A slight slope or a location with some natural barriers will offer better protection from prevailing winds.
• Orientation:
  In most cases, it’s best to align the polytunnel so that the narrow ends face the prevailing wind direction. This reduces the surface area exposed to the wind, minimizing the risk of damage.

2. Anchor the Frame Deeply and Securely

The frame is the backbone of the polytunnel, so securing it firmly into the ground is essential in windy areas.

• Ground Anchors or Stakes:
  Use heavy-duty ground anchors or stakes to secure the polytunnel frame. Spiral anchors that screw deep into the ground offer extra stability and are particularly useful in loose or sandy soil. For areas with very high winds, concrete footings for the frame legs can provide additional security.
• Ground Bars:
  Ground bars, or base rails, help anchor the entire structure to the ground. These can be pegged into the soil or, for a more robust solution, buried in a shallow trench filled with soil or gravel. The weight of the earth helps hold the frame securely in place.
• Trenching the Frame:
  Another method is to dig trenches around the perimeter of the polytunnel and bury the frame poles. This method provides a strong anchor point and is particularly effective in sandy or unstable soils.

3. Use Strong, High-Quality Polythene

The cover is the most exposed part of the polytunnel, and choosing a high-quality, durable polythene is key to withstanding wind pressure.

• Heavy-Duty Polythene:
  Opt for thicker, UV-stabilised polythene, which is less prone to tearing in strong winds. A polythene with a thickness of at least 720-gauge (180-micron) is recommended for windy areas.
• Anti-Hotspot Tape:
  Applying anti-hotspot tape to the frame where the polythene comes into contact with the metal bars will reduce friction and heat buildup, preventing premature wear and tear on the cover. This simple step can significantly extend the lifespan of the cover.
• Proper Tensioning:
  Ensure the polythene is stretched tightly and securely across the frame to prevent flapping in the wind. Loose, flapping polythene is more likely to tear or become dislodged. Tighten the cover using a rope or wire system designed to hold it securely in place.

4. Add Extra Fixings for Stability

Reinforcing your polytunnel with additional fixings and supports can help it withstand strong winds.

• Storm Braces:
  Consider adding storm braces, which are diagonal metal supports attached to the frame. These braces help to reinforce the structure and reduce the risk of it buckling under wind pressure. Storm braces are especially useful for larger polytunnels, where the structure may be more vulnerable to wind damage.
• Cross-Bracing:
  Another option is cross-bracing between the hoops, which provides additional lateral stability. This can be done using strong wires, ropes, or metal bars fixed diagonally across the frame.
• Extra Clips and Fasteners:
  Using additional clips or fasteners to hold the polythene in place along the frame is a good idea in windy areas. More clips will spread the force of the wind over a larger area, reducing the likelihood of tears or the cover blowing off.

5. Secure the Base of the Polythene Cover

Properly securing the base of the polythene cover is just as important as securing the frame. This prevents the wind from getting underneath the cover and lifting it.

• Trenching the Polythene:
  One of the most effective ways to secure the polythene cover is by trenching. This involves digging a trench around the perimeter of the polytunnel and burying the polythene edge in the soil. The weight of the soil keeps the cover firmly anchored, reducing the risk of it being lifted by the wind.
• Timber Battening:
  Another method is to secure the polythene with timber battens. This involves attaching the bottom of the cover to wooden battens and then pegging or bolting them to the ground. Battens provide a sturdy, even tension along the entire edge of the polytunnel, preventing the wind from lifting the cover.
• Heavy Objects:
  In some cases, heavy objects like bricks, large stones, or sandbags can be used to weigh down the edges of the cover. This is a quick and inexpensive method, but it may not be as secure as trenching or battening, especially in very windy areas.

6. Create Windbreaks Around the Polytunnel

Creating artificial windbreaks can reduce the impact of wind on your polytunnel by disrupting wind flow and reducing its force.

• Fence Windbreaks:
  Erecting a windbreak fence, such as a mesh or slatted fence, around your polytunnel can provide a barrier against strong winds. Be sure to position the fence at least several metres away from the structure to avoid creating a “wind tunnel” effect, which can concentrate wind pressure rather than reduce it.
• Living Windbreaks:
  Planting a hedge or row of shrubs around your polytunnel is a natural way to reduce wind speed. Plants like willow, hawthorn, or even bamboo make excellent windbreaks. These living barriers not only protect your polytunnel but also enhance biodiversity in your garden.

7. Regular Maintenance and Inspections

Regularly inspecting and maintaining your polytunnel can prevent minor issues from turning into major problems during windy conditions.

• Check Fixings and Tension:
  Periodically check that all bolts, stakes, and fasteners are secure and that the polythene cover remains tightly stretched. Replace any damaged or worn parts as soon as possible to avoid failures during a storm.
• Inspect for Damage:
  After particularly windy periods, inspect the structure for any signs of damage, such as tears in the cover or loosening of the frame. Prompt repairs will prevent further deterioration and keep your polytunnel in good condition.

Conclusion

Securing a polytunnel in a windy area requires careful planning, sturdy materials, and ongoing maintenance. By selecting a sheltered location, using strong anchors, reinforcing the frame, and ensuring the polythene is tightly secured, you can significantly improve your polytunnel’s resilience to high winds. Combining these strategies with natural or artificial windbreaks will provide additional protection, ensuring your polytunnel stays firmly in place, even in challenging weather conditions. With the right precautions, your polytunnel can thrive in even the windiest parts of the UK.