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Best floor for greenhouse?

Posted: Sat Jan 14, 2017 2:35 pm
by Kiwi Fluff
I've just bought my first greenhouse :cheers: but I'm not sure what kind of "floor" is best.

My options are:
Soil
Slabs
Pebbles

Or a combination of the above.

My mother in law seems to do ok with hers (half goes straight into the earth, half is paved for staging). Only problem is the soil beneath where it's going to go is quite rocky, would raised beds work or be susceptible to frost being above ground?

Thanks.

Re: Best floor for greenhouse?

Posted: Sat Jan 14, 2017 3:36 pm
by diggernotdreamer
I think a combination works well, I had a slab path up the middle, to work from and it is really handy to be able to damp down the greenhouse in hot dry weather onto those slabs to provide some decent humidity. I had stood my greenhouse up on quite high bearers to it was above ground level and then put wood across the front and filled in with good soil to plant directly into, the greenhouse was quite nice and high, you still have to be aware that frosts can get into a glasshouse whatever you do. I had a bit of wood cut to the size of that beds that could cover them if I wanted to stand pots on top in the winter or in spring when I had a lot of stuff in trays waiting to go outside.

Re: Best floor for greenhouse?

Posted: Sat Jan 14, 2017 3:41 pm
by Odsox
Raised beds would be just fine and what's more they would heat up quicker in spring.
It depends a bit on what you intend to grow, if you plan to grow tomatoes/cucumbers/peppers then a paved floor would need grow bags that would need watering twice a day during hot weather (unless you devised automatic drip irrigation), where plants in a soil bed would be quite happy being watered every other day or so.

Doubled with DnD, I have a small aluminium greenhouse that I mounted on a single course of 8" concrete blocks and then carried on pretty much like DnD did.
I'll take a photo later as it's easier to see than to describe.

Re: Best floor for greenhouse?

Posted: Sat Jan 14, 2017 4:25 pm
by Odsox
GH1.jpg
GH1.jpg (219.93 KiB) Viewed 1075 times

Maybe I should have swept the floor before taking the photo !


GH2.jpg
GH2.jpg (227.06 KiB) Viewed 1075 times

You can see on this one that you step down into the greenhouse, which gives more headroom.

Re: Best floor for greenhouse?

Posted: Sat Jan 14, 2017 4:56 pm
by Kiwi Fluff
Thanks for the photos Tony, that's exactly what I had in mind but had never seen it executed. Fantastic! Not sure I need the extra headroom though :lol:

DND great advice re. being able to raise the humidity with slabs. I'd never even thought of that (in fact I was considering pebbles so the drainage would be better :scratch: this makes way more sense).

Re: Best floor for greenhouse?

Posted: Mon Jan 16, 2017 10:14 am
by bonniethomas06
I am having the same issue KF, as soon as I can reclaim the greenhouse from the chickens (we have avian flu restrictions here) I will need to lay a floor. If cost was not an issue, I would go for slabs 2/3 of the way, with a bed for planting. Don't think I would like beds on both sides, as some things (aubergine, chilli etc) I want to be able to grow on my staging in the summer.

But slabs work out a bit costly here, so I am going for small pebbles/shingle instead. As well as helping with humidity, they will also hopefully act as a heat sink and help to regulate night time temps.

Only problem I have found with shingle is that if you have muddy boots, the stuff sticks to them and you end up trampling it all over the garden - might have to get some crocs just for the greenhouse that I leave inside the door!

Re: Best floor for greenhouse?

Posted: Mon Jan 16, 2017 11:08 am
by Green Aura
We used decking tiles (I'm sure that's not what they're called - the smallish square cheat decking thingies :lol:) over weed membrane and 1" stones on the not-raised beds. We grew most of our tomatoes etc in ring culture pots so they could dip their roots into the soil and we could keep it humid by watering the stones.

Re: Best floor for greenhouse?

Posted: Mon Jan 16, 2017 12:40 pm
by bonniethomas06
That's a good idea Maggie, will look into those.

Re: Best floor for greenhouse?

Posted: Mon Jan 16, 2017 1:00 pm
by Odsox
All my paths in the tunnels and greenhouses are concrete. Easy to use and a lot cheaper than anything you've suggested.
But then I'm a mean old sod. :icon_smile:

Re: Best floor for greenhouse?

Posted: Mon Jan 16, 2017 7:13 pm
by Skippy
I have two greenhouses and both floors. The first was built on an exsisting slabbed area when I first moved in. The whole floor is slabs and I use staging to grow tomatoes or whatever on. The second greenhouse is one I was paid to remove , which I did and then repaired it for my own use. It has a soil floor and a small central slab path. In terms of their growing potential I don't really see much of a difference. However , there is one , shall we say , disadvantage with the slab floored one. Being cleaner and to a degree drier it's very easy to just plonk stuff in there "temporarily "and it has happened when come the spring I find I haven't got a greenhouse , more of a glass shed.

Re: Best floor for greenhouse?

Posted: Mon Jan 16, 2017 8:06 pm
by diggernotdreamer
you could always chuck some woodchips down, I have those in my polytunnels at the moment, but I really am considering concreting my paths. Have an ask on free sites as well for second hand slabs, I used to get them for nothing by asking on Freecycle

Re: Best floor for greenhouse?

Posted: Tue Jan 17, 2017 10:38 am
by Odsox
When I got my first tunnel I made the paths with weed membrane with wood chips on top. That was OK for the first year but then I had weeds spring up on the path and their roots went through the weed membrane into the soil beneath, which were virtually impossible to remove as pulling them up lifted the whole path.
Also wood chips attach themselves to the soles of muddy wellies and get redistributed.
So now I concrete the paths which stops most of the weeds (I still get the occasional weed in the crevices on the edges) plus I can sweep the path (or not)
I imagine that weeds might be a problem in the gaps between paving slabs too, unless they are properly laid with mortar joints.

Re: Best floor for greenhouse?

Posted: Wed Jan 18, 2017 9:57 am
by bonniethomas06
I would definitely prefer concrete, but our greenhouse is on our 'agricultural' land and therefore in total breach of all planning permission!

So don't want anything too permanent, in case it has to come up one day.

Re: Best floor for greenhouse?

Posted: Wed Jan 18, 2017 6:45 pm
by Green Aura
I reckon you'd have a fairly strong case for arguing a greenhouse is an agricultural structure.

Re: Best floor for greenhouse?

Posted: Wed Jan 18, 2017 7:07 pm
by Odsox
bonniethomas06 wrote:So don't want anything too permanent, in case it has to come up one day.

A concrete path is not that permanent, you don't need any foundations, reinforcing or anything, just remove the grass and lay a couple of inches of concrete.
If you need to remove it, a hefty blow with a sledge hammer and you can pick up the pieces.