[prakash_mib]

I would like to build a polytunnel diy to keep the costs down.
I would like some advice please. Here is my design work.
The idea is to have 16-18 feet wide (plot width 25 feet) and about 30 feet long with hoops running at every 5 feet.
Plannis to have 48.3 mm scaffolding pole 2 metre ones staked 60cm down with postcrete And run MDPE pipe 63mm hoop.
For stability i might use strip of wood running under the hoop one at top and one on either side and the top being set with wooden pole underneath. Ventilation for summer months would be debris netting doors at both ends and with attachable poly lining  for winter months.
And also thinking of running gutter with extra polythene down one either side.
The end face of the tunnel would sit flush facing west so i might have to put in the end about two metres away 4 poles with debris netting to reduce the wind hit.

Questions
Is this crazy idea or practical
How to collect rain water into IBC(s). Thinking of putting atleast 4 IBC and run a tap inside.

And most of all is it worth the effort? Never had any greenhouse or anything. I know this is a big undertaking but son is getting into gardening as well and he enjoys ait. So i want to have good time before he fly the nest.

[Yorkie]

I can't answer your technical questions, sorry, but have you double checked you'd be allowed such a large PT on your allotment site?  Some sites have restrictions on sizes.

[mumofstig]

Some pics here PAULS ALLOTMENT DIARY: Build Your Own Poly Tunnel

Or watch the building of one on youtube  https://www.youtube.com/watch?v=n4o7SL4KZNA

[prakash_mib]

Thanks Yorkie snd MOS.
Got message from allotment that i can build 10x30 ft PT. so good news.
Bad news us they want me to build it where the established current and gooseberry bushes are and my shed as well, Which is a pain.
Although we don’t use currants the Mrs taken liking to gooseberry. Which means i can only make the move in winter.

[Longshanks]

I made one out of MDPE and random bits of wood. It measures 5mx3m. Sadly, I used 22mm MDPE which isn't strong enough to give a decent arch. This was given to me, so I couldn't say no. I bought a BIG roll of polytunnel covering from Ebay for £30. Originally from Northern Polytunnels or similar name and it's very strong. It took a direct hit from Storms Ciaron and storm D whatever and I had to make some modifications by lowering the height. It was a bit of a mess.  I'd recommend having trenches at either side and laying the ends of the polythene in them and covering with earth and bricks. Mine didn't blowaway, just sort of collapsed as I couldn't get the right tension.

Today, despite both ends being open (used plastic zips) and being sort of in the shade of a tree, the temperature was 45 degs C at 10:30.

I'm taking it down after summer, but reusing the plastic to build a geodesic dome using a kit.

[johnjsdb]

I used  the same size pipe and MDPE pipe for mine and some strengthening planks on the sides, it survived the winter fine, mine is 4m X 2.7m, stuck the scaffold pipe about 1m into the ground and made a frame for the doors on either end, plastic was from Northern Pollytunnels via e bay as they sell two widths by the meter, I think you can get 7.4m and 9.2m
Some photos if they help