polytunnel plastic

[mrjarraman]

Ive acquired 4 rolls of new, strong clear plastic. I intend to build a polytunnel.

My neighbour has advised me that it might not be the "right type". This threw me as being new to this thought all plastic was the same.

My question is, is there some plastics that CANNOT be used? Many thanks.

[ESBkevin]

I think the problem is UV or ultraviolate light. Polythene for normal use will break down in a matter of months when exposed to sunlight and start to go brittle/crack. Next you are left with a million bits of crumbly plastic in your soil and no polytunnel. So a special type of plastic has to be used, also pond liners are subjected to the same problem which is magnified where the water meets the plastic. For all the good the Sun does, this can be a problem.

I'm not and expert and don't have a tunnel.

[greenishfing]

I don't know much about plastic but I do know that some is unsuitable and if exposed to the elements becomes opaque very quickly and then disintegrates. The only reason I know is that my husband wrapped something in some to store it outdoors.

[Thelma Sanders]

Some plastics degrade very quickly in sunlight.
If it isn't resistant to Ultraviolet light, it would probably only last a year - is it worth all the trouble of fitting it for just a year? That's your decision..

[mrjarraman]

Brilliant advice, many thanks

[Small pumpkin]

Does your plastic have anything printed on it that would help identify it. Most polytunnel plastics do.

[nickdub]

the poly-tunnel plastic should be marked horticultural grade or similar when you buy it

I put up a 10m x 4m poly-tunnel 2 years ago using a galvanized steel frame off Ebay for about £60 and a large roll of plastic solemn-else had bought to do one themselves and changed their mind mid-project (about 14m x 5m cost around £50 I think).

Main thing I'd say -apart from the normal stuff like getting everything square and level before you start + anchoring it down to the ground so it doesn't become a large kite, is to really stretch the plastic cover before you secure it - left mine a bit too loose through missing that point - really a two man job at that stage imo.