High Winds Can Wreak Havoc On Greenhouses, Polytunnels And Gardens. Learn How To Reduce Greenhouse Wind Damage Here.
Named winter storms increasingly cause garden havoc with polytunnels blowing away, polycarbonate sheets being blown out of greenhouses and glass shattering. Dreams are also shattered … so the question has to be How To Reduce Greenhouse Damage caused by high winds?
Having owned half an acre of glasshouses and the same area of 14ft and 1§8ft wide tunnels I really understand how devastating wind can be. In my mind there are two ways to reduce damage.
Make the structures more secure
Reduce the wind speed.
Both are possible. For example polytunnel sheets can be buried in trenches around the whole perimeter of the polytunnel. Glass can be held in grooves rather than depending on clips to hold it in place. Commercial greenhouses, almost without exception, secure the glass in grooved frames. For some reason, perhaps cost, amateur greenhouses usually depend on fragile spring clips to hold glass in place.
But, should w not be able to trench sheets in situ or put our glass in grooved glazing bars, all is not lost. We can also attempt to reduce the wind speed. And that is much easier than many people imagine. The secret is not to put up solid barricades such as fences. They just lead to wind turbulence and can even increase the wind speed. I’ll not go into the science behind that but, if you are interested, look at the Bernoulli principle! It is very similar.
Better than trying to stop the wind we should try to filter it with semi permeable structures such as hedges, trees, and tall flexible plants such as bamboo. And rather than a single belt of natural filters try to stagger them a bit so the the wind is slowed down but is not forced into turbulent behavior.
Rather than write a very long article on wind speed reduction I have added some short notes below. Feel free to pose questions in the comments section or on social media.
Wind Speed Reduction Windbreaks
Natural Windbreaks: Plant dense hedges or rows of trees on the windward side of your greenhouse or garden. Evergreen trees and shrubs are particularly effective. Personally I love to use bamboo as it is springy which means it flexes without breaking. In many ways this is more effective than solid windbreaks, even natural ones. And you can harvest bamboos for garden use as it grows. Choose non invasive varitioesd!
Artificial Windbreaks: I prefer not to use solid windbreaks for the reasons previously given, but sometimes there are no other options. Use fences, walls, or specialised windbreak netting such as Rokolene to create a barrier against the wind. One of my preferences is to use trellis to slow the wind speed. In summer it can support plants and produce some dappled shade. And in winter it filters the wind.
Combination: Combine natural and artificial windbreaks for maximum protection. But remember to stagger wind breaks so that the wind is encouraged to weave through the area and hence slowed.
Strategic Planting:
Wind-Resistant Plants: Choose plants that are naturally resistant to strong winds, such as tall decorative grasses (including bamboos) and some shrubs.
Staggered Planting: Plant taller plants at the back and shorter ones in front to create a gradual windbreak. Part of the idea here is to slowly dissipate the wind force and direction. Think of it like a natural chicane that deviates the wind off course. Either over the top of th structures or to the sides.
Grouping: Group plants together to create a more cohesive and wind-resistant mass.
Greenhouse Protection:
Reinforce Structure: Securely anchor your greenhouse to the ground. If need be reinforce its frame to withstand strong winds. But if you need to do that it is clear it isn’t designed and manufactured to high enough standards. Ditto if you need to silicone polycarbonate into frames. It shows the design is inadequate. Unfortunately it isn’t possible to use glass everywhere. Some allotments ban it for what they consider good reasons.
Ventilation: Ensure proper ventilation to prevent wind pressure buildup inside the greenhouse. People think me mad but I ensure the gable ends have a small area left unglazed when high winds threaten. I want the wind to be able to blow through the structure. The worse situation is where, for whatever reason, the wind gets in and has nowhere to escape. It is like having a huge windsock where the pressure builds up until the glass breaks or the whole structure flies into the sky!
Clear potential debris from around the structures. One of the biggest threats to polytunnels and greenhouses is flying debris. From cloches and empty water barrels to buckets, wheelbarrows and badly maintained sheds, flying rubbish is going to cause a lot of damage. From experience I know a lot of allotment damage is caused by debris flying from plot to plot. Glass hit by a bucket or pot flying through the air at 50 mph hasn’t a chance.
Amazingly glad sis however very strong. I’ve seen glass in grooved glazing bars start to slide out of the grooves and, when hanging out nearly half it length, it will bend a huge amount. Glass is actually very flexible. It is also very rigid and can’t be compressed much. Squueze it sideways and it has begs strength and structural integrity. BUT .. flick a bit of grit at it and it shatters. Once you understand glass you are going to be far less likely to see broken glass.
Additional Tips:
Monitor Weather: Stay informed about upcoming weather conditions and take precautions before strong winds arrive.
Secure Loose Items: Tie down or bring indoors any loose objects that could become projectiles in high winds. Honestly, This is VERY important.
By implementing these strategies, you really can significantly reduce wind speed and protect your greenhouse and garden from damage.
