polytunnel - side or end on to wind?

[Katog]

What do you think is best - to erect a large polytunnel - side or end on to wind?

[Two_Sheds]

My instinct tells me face the smallest area to the prevailing wind ?

[yekim_4321]

Would agree with 2sheds smallest area into wind.....less resistance...less chance of damage?

[veggiechicken]

Probably better ventilation too if you need a through breeze to cool things down

[RedThorn]

I would put curved side to the wind to reduce risk...

[Thelma Sanders]

wind to curved side here, wind goes up and over rather than being faced with flat side resistance.

[Feral007]

So, just to make it more interesting......we have the wind from either the west or the east. Reallly fierce winds too. So if I put the poly tunnel I'm planning end/end north and south will that work?

[RedThorn]

in my estimation, you can have a curved side to both east and west unless your poly tunnel is a dome then you don't have a worry

[Feral007]

With the wind gusts we get I'm pretty sure a dome is 'all trouble'

[marchogaeth]

Firstly, I'd get a book and read the chapter on siting your tunnel and then make a decision.

Unless you are getting it second hand, get in touch with the supplier(s) and pick their brains.

This is how I understand it:-

• You do not want the wind having direct access into your tunnel. It can reek havoc with the plants especially if you only have one set of doors open.
• Also it will bash your doors constantly when they are shut and could force them open so you will have to put weights against them to be confident they won't burst open. (This happened to me due to suction even with and EW alignment.)
• You also have to think about getting sun into your tunnel. Most people site as close to east/west on the long side to get the maximum sun and minimum shading. At the same time you have to allow for nearby trees/buildings, access points and the arc the sun takes in the sky through most of the year.

How bad are the winds? I think people under estimate how strong a well errected tunnel is. Mine is 7m long and is in a constant wind (well apart from 30 days a year) which can reach up to 60mph.

I bought the size of tunnel I did because it was the smallest size that had heavier tubing (although I'd have had one twice the size if I could!) and I fitted crop bars which add stability. When I spoke to my supplier (who is fairly local), they were really helpful. We talked about the site and they felt even with the gusts I was expecting that I didn't need wind struts because I was burying the plastic.

We have planted trees to make a wind break but they are still tiny. You could think about using willows or something to create a quick growing wind break.

Alternatives are to use bubble wrap type polythene which is apparently stronger the ordinary ploythene.

[Uber-Uncool]

Curved side to the wind IMVHO

[Urban]

Think I would site it to make best use of the sun, and not worry about wind direction, the wind seems to come from any direction these days

[VirginVegGrower]

East West is always the advice on siting polytunnels or greenhouses. Wind changes direction all the time.

[Feral007]

Our winds can get up to 125 kph. I can see the point of having the curved sides to the wind. Since our wind is either from the west or the east then that will work for us.

Not sure how much I will have to bury the plastic to keep it down tho. I am planning to make a temporary one as in summer it would cook everything. I'm thinking some plastic spring and autumn and shade cloth in mid summer. Wish me luck! Not a lot of people use them here (except those growing cash crops of the type that we wouldn't mention, and they don't usually share their secrets!)

[RedThorn]

What about a fixed plastic to about 4ft off the ground and zippers( or heavy duty press studs or something for easy changeover) along length so you can swap between shade cloth and plastic? This way providing a wind break and flexibility....