Greenhouse vs Polytunnel

A similar question https://www.growfruitandveg.co.uk/gr...nel_95687.html

Thanks Veggiechicken,
That’s helpful. I did look to see if someone else had asked but must have missed that post.
It certainly answers some of my questions but not all of them. I would still be interested in people’s views.

I think I've asked the same question myself - can't find it though.
What is your plot like for security and vandalism? That would be my concern if I was spending big money on a GH or PT.

Security is quite good to be honest.
We’ve got padlocked gates which have the combination changed periodically.
There were issues with vandalism a few years back but it’s been ok since we had the gates installed.
The plot next to mine had a 12‘ by 8’ greenhouse installed last year and it’s been untouched by thieves and vandals. That plot had a paved area at the front so was relatively easy to install a greenhouse there.
My plot is almost all cultivated so would present a different challenge if I wanted a greenhouse. I’ve got one “solid” space which currently has a derelict 6’ by 4’ greenhouse. The frame is bent, there’s no glazing and the door’s missing. It’s probably not worth renovating as I want something bigger anyway.

Hi Lymmguineas
By greenhouse I assume you mean a glass paned greenhouse?

What can I grow in a greenhouse that I can't grow in a tunnel (and vice versa)?
To my knowledge it's no difference, but polys can plant in beds and dig into the earth easily, not sure abt gh. Can grow more stuff in poly, probably

What are the advantages/disadvantages of each?
GH, if one pane breaks, airflow is disrupted and the other panes follow soon. If you're not on top of it you're stuck with a a pileful of glass which is downright dangerous. Not sure how you source and fit the broken pane but even maintenance wise could be more expensive. They're really attractive though and sturdier than polys
Polys aren't that dangerous, can put up and down. Low maintenance, just patch up if get a hole, rebuy a cover to fit the frame if tearings really bad. Cover needs replacing, maybe 3-5yrs maybe longer if not too windy. Major disadvantage in wind, may need to remove cover in winter to protect from winds.

Am I correct in thinking I can put a tunnel directly onto a bed providing I anchor it somehow but would need a more solid base for a greenhouse?
Correct, somewhat.
The trick with a poly is, don't just anchor, BURY it. Bury the metal base all around, tuck the cover in and bury that too. Don't let any wind go up from under the cover - it'll blow away. Hard work in the beginning but believe me, worth it. Polys can go on slight slope. Usually bigger, higher than gh so more room to move.
GHs I've seen were all on on solid base but maybe u could put on earth and use ground anchors to the frames? If not, with the gh you will lose all earth space on ground for growing. If you can ground anchor the GH are you going to be digging in there and are u spatially challenged like me and might shove a spade through a pane in the smaller space?

Tunnels seem to have a darker/opaque covering whilst greenhouses are clear. Why the difference?
Shading. Seed packs say full sun, my experience says some plants, like cucumbers actually don't do too well in direct, bright sunlight like we were getting and need some light shading. Yes, I know nobody ever says that. It's not a major issue really.

If I may, think about the wind. Very strong winds get a GH, it will rip your poly or blow it away completely. Unless you are getting a Keder polytunnel ***drool***. In a sheltered spot on a rented allotment site I'd definitely do poly. Unless I was trying to win a pretty plot contest or impress someone.

When you say polytunnel, are you considering the cheaper kit types you can pick up on Ebay (typically green, sometimes referred to on this forum as a 'blowaway') or a small commercial quality one from a dedicated polytunnel supplier?

That's fantastic. Thanks very much for the info/advice.

I'm not really sure Bario1.
Is it a case of "you get what you pay for" and the cheap ones are a waste of money?
The ebay ones are tempting because of the price....
On ebay, I can get something 6m x 3m for £160.
I've looked online at a company called firsttunnels and a 6 foot by 12 foot tunnel looks like costing over £360.
Not having bought a tunnel before I'm finding it tough to decide. As we're into Autumn now I'm not in a rush to buy something just yet but would like to decide on the type of thing to buy.

This time of year you might find deals on polytunnels - the ones at about £150 or less will tend to have Chinese 'steel' that is as strong as something that isn't very strong - reinforce with wooden battens and expect to see damage in strong winds. Having said that there are about 3 on my site - next to a road named WIndmill Lane right on the north coast of Devon - that are approaching their 3rd or 4th winter. Have needed a bit of repair but doing fine. Don't let the wind in them though as a flapping door will lead to airbourne covers if the wind gets up...
At the sub £150 price I'd be looking at 2nd hand greenhouses - as said make sure you replace broken / missing panes. Our site doesn't allow glass so people have to use the plastic alternative to agricultural glass sheets - works well for them though...

I think the stronger/thicker galvanised frames are an improvement for the ebay type ones, but the green covers only seem to last a couple of years before the clear plastic 'windows' in the green mesh start to drop out. I ended up in year 2 with a self-watering polytunnel, the frame is still going strong as a bean frame, though

You certainly get what you pay for, but that doesn’t mean the cheaper ones are a waste of money, you might just find you have to do more repairing/replacing/maintenance over the years. I bought a 6x12’ from the site you mention in 2013 and it still looks like new, I never have to worry about it, but it was about £400 and took 2 weekends to put up!

Looking at some of the chap tunnels online you see some that have 20mm tubes that are connected via plastic connectors. To be expected in a small cheap temporary 6x4 green house for a few quid but to be avoided in a larger polytunnel.

Tunnels can be found with thicker 32mm galvanised tubes which are joined either through swaged joins or bolts and should be stronger. The green covering will only last a few yeas but if you have a sturdy frame you can recover it with poly-tunnel polythene which again will eventually wear out and need replacing.

I got given a poly-tunnel the other week (20mm tubes 3mx2m) as well as some scaffold board which will form the base for it. I'm trying not to spend anything much on it and use what I have as I only expect the frame to last a couple of years and the cover even less (it'll probably be more repair tape than cover anyway) - the cost of these replacement covers is almost as much as a poly-tunnel and as I don't know what brand it was there's no point just guessing and buying one that would probably not be a perfect fit.

I have one in the garage with 32mm tubes 6m x 3m that I haven't gotten round to putting up. Cost £160 and I'll end up spending a similar amount on a base/beds for it (18m of scaffold boards, plus lots more boards fixed to frame for the beds) and various bits to secure it and make it more rugged and flexible. Frame will be fixed to the base as will the cover, which will then be buried and base staked, etc.

Even at £320+ a 20' by 10' poly tunnel should be worth it. I couldn't afford a similar sized greenhouse.

The ground needs a lot of prep to level it and clean out the crud so I'll be doing that on my holidays off work.

My greenhouse is 10'x8' and is great but the poly-tunnel provides a whole load of additional space.

Greenhouses make me laugh. We get them to provide the extra warmth for our plants and site them in a nice sunny spot then spend the summer making sure that we ventilate so they don't get hot and covering in shade cloth/whitewash so they don't get too much sun. Gardeners are a tough lot to please

I've been looking at the Northern polytunnel site. It has a 'needs some DIY - for allotments' polytunnels. They seem to be inbetween the cheapies and the very expensive/heavy-framed models.
I'm seriously tempted, I must admit, now I have the bigger plot

https://www.northernpolytunnels.co.u...olytunnel.html

To me Northern Tunnels and First are about much and such for build quality. You get what you pay for base rails and doors.

The Allotment polytunnels don't have doors, so you still need all the woodwork to complete. If you don't have a good skip, sawmill or builders merchant (and don't want to trench in the plastic) get one with the base rails and doors.

I'm very pleased with the tunnel and it is cost area benefit that does it for most people. I'd like a proper greenhouse next to house for nursery / propagation space... will see