polytunnel advice ?

[MuddyWitch]

My tunnel is 12ft wide & 25ft long, but I dug out about a foot of soil so it's about 7ft high to the crop bars. I would do this again in this tunnel, because it has a membrane right across the floor and I plant in pots or buckets, not into boarders within the tunnel. I stand those mini-greenhouse inside with their 'jackets' on and steal a lead on Spring.

If I am lucky enough to be able to afford a second one after our move I'll go for a 14ft by 25ft so that I can have proper boarders and grow directly, so I'll just dig out the paths.

By-the-way, t'isn't me that does the axe wheelding, t'is Mr MuddyWitch, and it's only the small hand axe, not the big tree felling one!

MW

[grahamhobbs]

We inherited 2 polytunnels on our allotment, both 30ft long, one I think about 12ft wide the other only 8ft. The polythene was pretty much gone, so we replaced it but added timber about 1ft off the ground to which the polythene was fixed and then allowed to drape to the floor. This'flap' can then be lifted to increase ventilation. Without these the 30ft long tunnels would not get sufficient ventilation.
The smaller tunnel has straighter sides, whereas the larger one is more of a half-circle - this causes a waste of space where only weeds grow.
Personally I prefer the narrower tunnel because there is a single narrow path down the middle and you can reach everything easily (the beds are slightly raised each side), so I think it is probably more productive than the wider tunnel.
I think a polytunnel used well and throughout the year will repay itself, I'm sure we get a lot more than £200 worth of veg out of each of ours each year. Currently we've got about 50 pak choi growing in one corner and a Malaysian friend said, when I gave her couple, that they would have cost her £1 each in the shops, so with basket fulls of tomatoes, sweetcorn, cabbages, winter broccoli, sweet pea, parsley, basil, winter salads, carrots, etc (and I will be adding over-winter peas) coming out of the same tunnel, it must be worth it - let alone the pleasure it gives in winter being able to work in the garden in all weathers - it turns your garden into an all year pleasure.

[shell]

i have checked out first tunnels and the prices and goods seem ok,tell me,what else do i need to start up/and do i need doors?i see a lot of accessories that you can add to your order,i might as well order them at the same time if i really need them,can any one get me through the maze of products advertised to what i really need ?and finally are they hard to get erected and what ground work is needed first?
lots of questions i know but someone may be able to help a novice like me
oh and it seems from previous posts that around 12 x25-30 is the best size to order,what works best for you?

[fruitcake]

Ours is only small - 10'x15' and cost just over £500, because we had to get the thicker frame and crop bars etc. to withstand the gales.

GA - I'm planning on getting a tunnel next year and was debating whether to put it end on or side on to the prevailing wind (gales!) - I had thought of putting it end on but a neighbour was suggesting side on ifor when the doors get blown open and gale blows it from the inside out - we're on a pretty exposed hillside here and the wind blows up direct from the sea loch - driving the rain uphill - luvverly!

Which way into the wind is yours? Any thoughts re ours?

ps the wind has already destroyed 2 of our sheds, doh

[MuddyWitch]

I'd recommend crop bars to every-one. Not only do they add structure but they are so useful:

But I'm repeating myself...have a quick read of this thread:

http://www.selfsufficientish.com/forum/ ... 12&t=12824

Or take a look at Odsox fab set-up

http://www.selfsufficientish.com/forum/ ... 12&t=13062

MW

[Thurston Garden]

Which way into the wind is yours? Any thoughts re ours?

I would go for longside onto the wind. The doors are the weakpoints. A good quality plastic cover with cope with significant wind assuming you get it fixed on well and it is as tight as you can get it. As MW says, crop bars provide significant strenght and most manufacturers will recommend them in exposed sites. I think as long as you don't let the wind under the plastic cover and keep a close eye on your tunnel for loosening bolts/clamps etc, you will be amazed at the punishing it will be able to take.

[shell]

thanks,now i know i`m getting 12x30,and crop bars,and doors come with it,sorted,i think now all i need is for dh to finish the back patio and erect his shed,and the polytunnel i hope will be the next

[shamie]

thanks for all the advice,what i meant by it paying itself off was, how long before i could save myself the price of it by growing say for instance tomatoes, we spend maybe 4 euros a wk on them, a couple of euro on lettuce,etc,etc, it wud make my growing season longer for certain veg and so wud not have to buy as much. dont know if that makes sense, i know what i want to say but am starting to confuse myself,ha ha ha !!!

[Odsox]

This got me thinking this morning, and that's a rather painful experience first thing on a Sunday morning.

The answer is surprisingly YES ... it will pay for itself.
My tunnel is 3.6m x 10m and costed €790, plus after 5 years it needs the polythene replacing at a cost of €180, so if you round that up to an even €1000.00 then over 10 years it will have costed €100 per year, or about €2.00 a week.
After 10 years of course it's pretty much just the 5 year polythene outlay which brings it down to about 70c a week (at today's prices)

So unless I'm totally wrong (and I'm sure if I am someone will quickly tell me), it should easily pay for itself by producing a lot more than €2 worth of home grown veggies every week.

Hope that helps.

[A&A]

I appreciate this thread is a little old, but there's some great advice already here and since so many people these days desire a polytunnel, it makes sense to continue adding thoughts to it ;)

I'd go along with the theory of it paying for itself although you can obviously save cash along the way by being a little inventive.

I paid €200 for the frame, €70 for the polythene (which was the best stuff they had out of a choice of 4 types) and then €6 per 6M of galvanized plumbing pipe (reclaimed from a builder's yard.) The plumbing pipe is particularly useful for bars along the sides of the tunnel. I further cut one length into sections and had it welded by a friend into a door. The commercial tunnels here are built similarly using plumbing pipe for the side bars. It makes it easy to roll them up & down and we buy clips/clamps here which fit the pipe perfectly and clamp the polythene tightly to both the pipe and the polytunnel frame. It's easy to get elbows and short lengths which screw together and make nice handles!

I raised my tunnel by sinking some 2ft lengths of old scaffolding poles into the ground (with a bit of concrete) and then dropped the tunnel legs into them & bolted them together. It gained me a fair bit of extra headroom & a slightly straighter side at the base.

Despite my hatred of cement blocks, I reconciled the cost etc vs wood which would need treating (no thanks) and probably replacing every couple of years. Wood simply doesn't last very long here unless it's pressure treated and then well looked after. The wood alone was going to cost us more than the frame of the polytunnel - so it was a no brainer to go with cement blocks - which will hopefully last forever.

I've routed electric & an irrigation system into the tunnel - it's been quite a project but I figured that if I was going to do it, I wanted to do it well and have it there for a bloody long time.

Almost finished (door still to build)



Some snaps taken today (11 Nov 09)





By the way, it's not going to blow away just because the sides can roll up ;) & in summer, everyone here fits some shading material on top of the tunnel (there are wires across the top to tighten the polythene further which also grip the extra material when it's added.)

[Millymollymandy]

Do you really need to use a polytunnel at all in summer in Italy? I would have thought it would be a furnace inside. I had a greenhouse when I lived in SE France and after May I couldn't go in it - it was over 50C in there, and that's with shading! I once had a plastic greenhouse here in Brittany for about 8 days (until it blew over and broke ) and even that was too hot in late spring/early summer.

[A&A]

No, you don't need it at all in summer - although here everyone does still use them for planting late tomatoes etc. Whilst it's very hot here, we had our first frost in mid October this year; it's well worth making use of it to prolong the season. It doesn't need to get that hot inside. I found that with the sides rolled up (they roll up all the way to the first horizontal frame bar), it was little different inside to outside temperature-wise. It's quite an interesting climate to deal with. We get a reasonable amount of snow most years until the end of March and it'll get down below -5C on occasion through the winter. Summer highs of around 40C. It's why Umbria is known as the 'Green heart of Italy'. You definitely need a polytunnel to get anything much over winter. I should add, that what it also gives us is the ability to start seeding in modules in mid/late January - a 2 month head-start on what would be possible otherwise - that's a lot of food ;)

[contadino]

Andy, that's a nice looking tunnel, and it's about the size of the one I'm after (the space I have in mind is 4m by 8m..?)

Where did you find a frame for €200, and do they do mail order? I got quoted around €1800 by 3 places, so am currently looking to build one using the plastic pipe technique. However, the price of plastic pipe knocks the cost up towards €180, and that's without the furling sides. Galvanised metal would obviously be a much longer-lasting solution.

[A&A]

Wow - that's pricey!! Mine is 6m long - although you simply buy the hoops & struts individually so adding on at anytime is quite straight-forward.

I got it from our local 'Consorzio Agrario'. I was over there a couple of days ago and noticed they still had plenty of frames in. This chain is all over Italy so you may find one close by. If they don't have them - they'll probably get them for you.

However, word of warning (isn't there always!) I had to over-come one or two 'issues' with it compared to the polytunnels that many of my neighbours have:

1. The tubes are square. Not initally a big problem you'd think - however, the clips that we all use to tighten & secure the plastic are round. Hmmm. They're not ideal - but they still do the job, just not quite as firmly as with the round tube tunnels.

2. It's quite low (about 6ft). I'm just over 6ft and it would have driven me mad getting a wet head everytime I went in there. I've raised it about 18 inches (more work) and it's perfect. The regular tunnels (that everyone but me and my 2 neighbours have) are all higher.

3. No door. You have to make your own. The other type come with a steel-framed door.

The side rail advice stands though- regardless of which tunnel you buy. From what I gather, no-one makes side bars for the Italian tunnels - even some other neighbours use the plumbing pipe - and their (professional) tobacco tunnels are over 25m long! Just make sure you get the appropriate pipe that'll fit the clips you can get. It makes the polythene fitting extremely simple. I reckon I could replace, cut and tighten the polythene on my tunnel within an hour now. Previously, I'd tried digging it in and could never get it tight enough to stop it rubbing. Done this way, it's very tight. Everyone does it the same way, and they all reckon on their polythene lasting for at least 5 years. Of course, by digging it in, you also lose the ability to raise the sides which I think is essential over here.

[Green Aura]

Andy, can I ask how you replace the polythene so efficiently. When we got our polytunnel it took 4 of us to put it on. Admittedly there was a breeze, but up here we get so few days without a wind we'd get nothing done waiting for a still day .

What's your technique (with pics if posssible )