As I was wandering around Instagram, I saw someone who was delighted at their fresh bunch of lettuce, in February, picked from their greenhouse when it was -7C wherever it is they are. I admit, I was jealous–and excited! It never occured to me that a greenhouse could produce lettuce all year round.
Then I realized that while murmurs had been muttered about possibly getting some massive greenhouse set up on the farm that I would have access to, the only thing I really knew for sure that I had access to is a polytunnel (and it is quite huge, something silly like 60ft). Then it dawned on me that I don’t really know the difference between a poly tunnel and a greenhouse as far as capability goes.
So I thought I would do some research and share what I found.
First, let’s look at the basics:
What is a greenhouse?
Greenhouses are those glass or super sturdy plexiglass houses to grow plants in. I know, that seems pretty basic, but they are generally what you think of when you think of keeping plants warm during their growth. And you guessed it, they look like a house.
On a page on RIMOL Greenhouses, the differences between a polytunnel and greenhouse is outlined. I’ll tell you more about what is said about polytunnels in a minute, but the page explains that greenhouses are more geared toward gardening with the four seasons, and this is because of the general use of a heating system within a greenhouse – something I didn’t know was a thing!
How you grow things is different as well. In greenhouses, you generally grow with pots on benches (though it’s not impossible to grow directly in the ground in a greenhouse), using hydroponically, or in grow kits.
What is a Polytunnel?
I won’t slate on anyone for not knowing this one mostly because before I moved to the UK I’d never really heard of one. Seen one, yes, but I didn’t know what they were called. They are those tunnel-like domes made out of clear plastic and PVC piping. I’ve seen them of all sorts of sizes, from portable to could-live-in size.
The page mentioned above says that polytunnels are more geared toward extending the growing season. Because they’re not actually heated, they just help to keep the frost off early growth and keep things warm enough to keep producing through the autumn.
In polytunnels you’re more likely to still have raised beds or plant directly into the ground (though you can still do pots and hanging planters, of course) as there is more ground area.
Pros and Cons of Each
Of course each has a reason to be used, but here is a side-by-side look at the pros and cons of each.
As I mentioned, I’m lucky enough that I have access to a polytunnel, which to me sounds like the one I mostly want. However, I will aspire to also have a greenhouse. The farmer whose land we’re on has said he wants to get us a big greenhouse so we can grow more food, though really all I want is a small one outside our kitchen window to grow my herbs in year round.