[stompy]

Hi all,

Which is warmer, a greenhouse or a polytunnel?

Just wondering what the pro's and con's are for each?

I now have an 8x12ft greenhouse and have had my first season with it but still feel as if i could do with more space!
I may be tempted to sell it and build a polytunnel instead, just not sure if it would be worth it?

[mumofstig]

greenhouse was warmer than poly according to thermometers, but poly always felt warmer cos it was more humid, if you know what I mean
Presumably if you manage the humidity (better than I did  ) by having open mesh panels, it would be even cooler in there.

Polys are great for adding more space, but I don't think I'd replace my greenhouse with one.

[stompy]

The reason i ask is, i was in a friends pollytunnel at the weekend and it did seem warmer/cosier than my greenhouse.

Also it would be the extra space as i could have a 20x10ft pollytunnel so it would give me much more growing space, and the sale of the greenhouse would pretty much pay for the pollytunnel.

The only thing stopping me is i do like the solidity of the greenhouse but as said not sure which is best, if there is something i am missing.

Just wondered why people buy pollytunnels instead of greenhouses?

[mumofstig]

Just wondered why people buy pollytunnels instead of greenhouses?

because they are less expensive than a comparable size greenhouse

[stompy]

because they are less expensive than a comparable size greenhouse

So thats it? so greenhouses are better than pollytunnels and people only buy pollytunnels because of price?

If you had the choice, would you have all greenhouses or all polytunnels?

[mumofstig]

Put it this way, when the cover on my poly went 'holey' I chose not to replace it and got another greenhouse instead 

But I know that other people do very well with their polytunnels, so you really shouldn't  just listen to me

[RichardA]

I have in order of buying  6 by 8 greenhouse, then got a 16 by 8 greenhouse and now also have a 30 by 14 polytunnel. I garden at home and was able to buy orchard next door as well so very lucky with room and security. I have power at greenhouses for small propagator as well
Poly is used as a covered garden in many ways with about 6 weeks extension on season at each end compared to open garden. Greenhouses tend to get used for raising bedding plants and then go over to tomatoes. Polytunnel has more floor space so cucumbers, early courgettes, butter nuts all have space and early in season new potatoes then later in season even chrysanths and cabbage can be given space.
Poly does seem warmest but that is not in fact reality if you look at thermometers the truth is I think the humidity and less ventilation and also lack of brightness in a poly gives that impression of cosiness thats seems like more heat. Greenhouses have auto vents and power so easier to vent and also add fans or warm air if required that I cant do in poly. I am across the big bridge from you if it helps to come and see what I do -- it is nothing special but it works for me.

[stompy]

Thanks for the responses guys,

I'll stick with the Greenhouse then i think.
And thankyou Richard for the invite, when i get a spare weekend day i may just take you up on your offer.

Andy

[JayG]

Interesting replies.    I didn't spend that long contemplating which to buy because I didn't want to be lying wide awake in bed on windy nights ( ) or wondering how long the plastic would last before replacement was due, but I did do quite a bit of research into the pros and cons of each.

As I understood it a polytunnel retains heat better than a greenhouse of the same overall size because of its shape (it traps more air) but by the same token it can get too hot in summer, mainly because of the lack of roof vents (which is where the hottest air collects.)

Not a straightforward decision, especially if you Google "Greenhouse extensions"! 

[stompy]

Which site Jay?

[JayG]

Which site Jay?

Hmmm. Doesn't look so promising when you restrict the search to UK sites, although there is a piece stating that "some manufacturers offer extensions."

Can't find out which ones they might be - maybe it's easier to upgrade or join two together:

http://chat.allotment-garden.org/index.php?topic=17301.msg213656#msg213656

and

http://chat.allotment-garden.org/index.php?topic=79045.msg889468#msg889468

[ricky]

hi i bought a polytunnel 4 years ago 42 feet by 16 feet brand new £600 delivered the same size of greenhouse would have been £4000 for glass and £2000 for perspex go for the polytunnel tunnel everytime altho you will have to recover it every 8 to 10 years £150 tops

[kosh42|EFG]

4m x 2m poly = £90 on Ebay. Decision made, especially as a greenhouse on my plot (next to the fence with a busy path on the other side) would likely end up full of half bricks with no glass left...

[shokkyy]

I just installed a 6M x 3M polytunnel a few weeks back, early days but so far I love it. It was a cheapy from ebay (£175).  No, the cover won't last forever (but is cheap to replace), but the frame is good and sturdy. Last night we had 40mph winds and it didn't budge an inch. And despite having a touch of ground frost last week, my chilli, sweet pepper and tomato plants are happily tucked up in there, giving me lots of extra time to get the fruit ripened so I don't have to pick them green. I'm planning to put two 1M x 5M raised beds in there, giving me a very worthwhile amount of protected growing space.

I do have a small cold greenhouse, but even before some of the glass panes broke it never felt as warm as this tunnel does. From what I've read, the siting of the tunnel matters quite a bit, because in order to work most effectively it needs to get the morning sun so it can store the heat for the day, not the midday and/or afternoon sun.

Not only do tunnels give you a huge increase in growing space for far less cost, but the other thing I find appealing is that they're not permanent. If I decide I want to move it somewhere else, I can do it very quickly and easily. There's no ground prep other than any raised beds you might have. And I think, as Richard says, because of the extra space they can be used as a covered garden rather than somewhere just big enough to cram in all the pots.

[stompy]

I just liked the feel and look of the tunnel inside compared to the greenhouse.
I think it's also because the cover is opaque that you are more enclosed and warm.

I'll stick with the greenhouse for now and see how i go next season, and if i need more space i may have to change over.

Thanks for all your answers guys.

Andy