Optimum size for polytunnel

[Alison]

OK, so now I have my own plot I'm trying to sort out a plan of how I'd like it to eventually look. Have managed with a small greenhouse at home for the past approx 10 years and intend to carry on using this. However, am dreaming of a nice poly tunnel on the plot. But, have no idea what size to get - yes I know that I'll fill whatever size I buy but am guessing it's not as simple as that. Ideally this will be used primarily for tomatoes, peppers, chillies etc but may try a few other bits and pieces also - maybe another go at sweet potatoes. Anyhow, I've found that my friend doesn't really get much advantage of the extra width of her 8' wide greenhouse over my 6' one and she would have been better going for a longer length rather than width due to problems reaching across the beds. Is this likely to be a problem for a tunnel also and what width is most space effective?

Hope that this makes sense, want to at least know what my ideal is and then start looking / saving!

[JennieAtkinson]

Alison - mine is 20 feet long by 14 feet wide. Basically 5 foot bays, so I could have gone longer. A couple of years ago i did put some pics on how I had mine set out which you might be able to find on a search. I find this a great size. I'm just about busting at the seams, but anything bigger would take a heck of alot of extra work for me and the time I've got to put into it.

I'm sure there will be others who can advise more "technically"!!

[Kristen]

Different tack: I was planning to get a plastic tunnel for "cropping" (and a greenhouse for propagation / house plants etc.), but I saw a 30' x 10' glasshouse on 3Bay, which I paid £400 for. I reckon that's probably better value than a plastic tunnel (which will need new plastic every few years). Just a thought ...

(some details on my Blog if you are interested)

[lynda66]

i would say the best size is ....... decide what you want to grow in it, work out how big each plant will grow, plus an area for seedlings, and a potting bench, and storage for the stuff you'll need

then get one twice the size, cos once you've started you'll find loads of other stuff to try

[Alison]

Definitely want a polytunnel as it's going to be up the lottie and a couple of the other guys have had trouble with broken glass where as there's been no reported problems with plastic. Also, the price of a large glass one would be far too high for what I'm willing to pay unless I got very lucky!

Basically although I want a decent size, I want it to be 100% useable space rather than with very wide beds that are no use at the back for example. I'm not fussed about potting or seedling space as I'm intending to start plants off at home in the greenhouse and any potting will either be done there or in the shed so that's one thing I don't need to worry about!

Suppose part of the thing is that I'm used to a simple greenhouse layout with a path down the middle and single width 2' beds either side. That wouldn't work with a wider tunnel so do you have more than one path down the middle, paths across or walk over the beds?

[nick the grief]

Definitely want a polytunnel as it's going to be up the lottie and a couple of the other guys have had trouble with broken glass where as there's been no reported problems with plastic. Also, the price of a large glass one would be far too high for what I'm willing to pay unless I got very lucky!

Basically although I want a decent size, I want it to be 100% useable space rather than with very wide beds that are no use at the back for example. I'm not fussed about potting or seedling space as I'm intending to start plants off at home in the greenhouse and any potting will either be done there or in the shed so that's one thing I don't need to worry about!

Suppose part of the thing is that I'm used to a simple greenhouse layout with a path down the middle and single width 2' beds either side. That wouldn't work with a wider tunnel so do you have more than one path down the middle, paths across or walk over the beds?

Hi Alison,

Get Bernard Salts book "Gardening under Plastic" it's the bible for polytunnel owners ( and would be owners).

You don't have to have a path down the middle you could have it with Staging one side then a path and then beds on the other side if you see what I mean. But you will definitely need one bigger than you think

Also you are best to go for one that is roughly square in foot print ( 60' x ' 8' isn't ideal as you can't ventilate it like a greenhouse easily you'd do better with a 30' x 16' as the centre will get more air).

I'm sure Piglet & Sewer Rat can give you more advice

[Alison]

Thanks Nick, have been looking for that book but it's out of print in quite a few places but will get hold of it eventually and I've got plenty of time yet as there's nowhere clear enough to site a tunnel yet anyway!

[nick the grief]

Bernard Salt's Book

There you go

[burnie]

All the "experts "say it's better to have a wide short tunnel rather than a long narrow one(if that makes any sense)as Nick has already said it's better for ventilation and therefore, less likelyhood of damp related diseases.

[Alison]

Bernard Salt's Book

There you go

Yeah, but it's temporarily out of stock! Waterstones seem to have it in though so will get it off them instead. Thanks anyway.

[JennieAtkinson]

Also think about the height of things you want to grow. I had a lovely plan for my tunnel a couple of years ago and it was only when I went to plant the sweetcorn I realised it wouldn't have enough height at the back to grow!

I have beds either side with a large walkway down the middle (covered in bark) and then in the summer I fill that with pots and grow bags. At the moment you have to walk a convuluted pathy to get from one end to the other, but it makes the best of all the growing space. If my side beds were any wider I wouldn't be able to weed the back of them.

I can also recommend Bernard Salt - great book. But have a look at First Tunnels site too and their pages on interesting articles

Here: First Tunnels Customer Service

I've learnt alot here.

[sewer rat]

A wider shorter tunnel, as already explained, is easier to ventilate - and ventilation is crucial as a large tunnel can get very hot and is not only unbearable for plants but also for you to work in. I have a 24' x 60' tunnel, with staging down the full length of one side, then a walkway and the rest is just one big growing area. I don't have raised beds - have a look at my album to see my layout.
This will change over this winter though, as I am changing what I grow in my tunnel, so I will have a series of raised beds, each 4' wide with a 1' walkway between each as I am going to grow a lot of lettuce and CCA salad mixes next year. I will also grow 40 cuke plants at one end of the tunnel, and have 70 odd cherry toms in hanging baskets fron the crop bars.
My tunnel is a First Tunnel one, with the plastic on base rails - this might be okay in the south, but up here in the windy Highlands especially on my open and exposed site, it's a real pain as if the plastic needs retensioned, I have to dig out a trench and then slacken all the U bolts before I can drop the base rails and then I have to do the whole thing in reverse. Northern POlytunnels allow you to tighten the plastic by undoing bolts on the inside and raising the hoops to tension the plastic - a much better idea for a bigger tunnel.

[Kristen]

"Definitely want a polytunnel as it's going to be up the lottie and a couple of the other guys have had trouble with broken glass ..."

DIY any good?

Making a DIY Poly Tunnel

[Alison]

"Definitely want a polytunnel as it's going to be up the lottie and a couple of the other guys have had trouble with broken glass ..."

DIY any good?

Making a DIY Poly Tunnel

Quite possibly, although not sure it would look that professional if I made it! Will show it to OH when he gets back from a trip away to gauge reaction

[lottie dolly]

thanks for putting this link up again about the home made tunnel,i have taken on board about the air flow in a longer tunnel,and see it has been suggested a shorter,wider one is more benefitial as regards to the air flow,my question is,if you have a longer tunnel,with a door and window open each end,then would that be enough to circulate the air to all parts of the tunnel,also sitting the doors east and west,with the long sides north and south,what you think.