What type of floor for my new greenhouse

[Babru]

Hi, I've looked through the undercover posts and haven't found anything to answer my question - sorry if it's been asked before.

I will be building a 6x8 greenhouse in the coming months (well, really I'm the labourer, other half is the main man). I plan to grow tomatoes, peppers, chillies at least initially, being new to greenhouses I want to start with mainstream things to see how it works.

I'm not sure what to make the base from. We've lots of slabs going spare and at no cost, or OH says he could do a concrete base. Alternatively slabs up the middle, with gravel at the sides to sit my quadgrow pots on.

I suppose I'm concerned with a couple of things: firstly pests and diseases and how easy it will be to keep clean and tidy, and secondly drainage. A concrete base, for example, how does the water drain away.

Any thoughts and suggestions would be welcome.

[nickdub]

I'd go with slabs down the center and leave earth beds at the sides if it was me - you can always add gravel later, but the ability to plant directly into borders or let plants root through bottomless pots is not to be sneezed at.

I would use either bricks or a cast concrete sill round the edges so I had something strong and level to set the sides on. I like a bit of extra headroom than what you get with most small GH's, so raising up the sides by 8" or so always appeals to me.

PS I also like to run a water pipe in through the floor from outside to in, before starting on much else even if it sosn't connected to anything - you will need water inside and odds on the supply will mainly be outside whether its a butt or whatever. worst case scenario you just have a useless bit of pipe in the ground not doing any harm

[veggiechicken]

Four of my GHs have solid floors - concrete or slabs - just because there was no option of putting them on soil. I "build" edged beds around 3 sides, about 2' wide, which are filled with old compost. I grow in bottomless pots resting on the compost or shallow rooted veg are grown in the bed itself.
There are small gaps between the slabs for drainage.

Photos at https://www.growfruitandveg.co.uk/gr...ml#post1572735

[SarrissUK]

I have my greenhouse on a concrete base that covers the whole area more or less, but it's only there because it was housing an old shed when I moved in to this house.

I agree with Nick that in an ideal world I would have 'beds' along each side where I could grow things. However, early on in the year I have shelving that can hold all my hundreds of seed trays and tiny pots that then gradually gets moved out in the garden as the plants that remain in the greenhouse shove them out.
So right now, I have tomatoes up to the rafters in the greenhouse, and two wooden shelves out in the garden lol
I will definitely combine Nick's advice to raise the greenhouse up by building a base for it to rest on, and I absolutely love VC's idea of building raised beds inside the greenhouse as part of that - thank you both! You've inspired me!

[Bren In Pots]

I've got a couple of slabs as a path with soil borders, I leave the racking in place and use wooden shelves early in the season after that I grow my toms through them.

[nickdub]

I've got a couple of slabs as a path with soil borders, I leave the racking in place and use wooden shelves early in the season after that I grow my toms through them.

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Thanks for posting your photo Bren - more or less exactly what I was trying to describe, but much easier to see from a picture.

PS for anyone siting a new greenhouse, don't forget the orientation and any shade from trees or buildings can also be factors.

[Babru]

I've got a couple of slabs as a path with soil borders, I leave the racking in place and use wooden shelves early in the season after that I grow my toms through them.

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I like the idea of using the staging as supports. Obvious really, why didn't I think of it! Thanks very much.

[Babru]

I'd go with slabs down the center and leave earth beds at the sides if it was me - you can always add gravel later, but the ability to plant directly into borders or let plants root through bottomless pots is not to be sneezed at.

I would use either bricks or a cast concrete sill round the edges so I had something strong and level to set the sides on. I like a bit of extra headroom than what you get with most small GH's, so raising up the sides by 8" or so always appeals to me.

PS I also like to run a water pipe in through the floor from outside to in, before starting on much else even if it sosn't connected to anything - you will need water inside and odds on the supply will mainly be outside whether its a butt or whatever. worst case scenario you just have a useless bit of pipe in the ground not doing any harm

Do you take the soil out every spring and replace it?

[hedgehogneil]

How important is the changing soil? I am going to install a 10x8 Rhino greenhouse in the next couple of months and while it will have two lots of staging on one side with gravel underneath, the other side is still undetermined. I was going for soil but then read about pests etc. and since it was mainly for tomatoes in summer/salad leaves in winter, figured I would not be best doing this since I wouldn't be rotating much.

I have since thought gravelling it and growing things in containers leaving no raw soil in the greenhouse. If soil is a better growing medium, it may be I need to have soil and go to the effort of changing it every year but seems a hassle.

Has anyone learned any lessons about this?
Thanks,
Neil.

[nickdub]

Depends really on whether you are planting directly in to the greenhouse soil or not. For most veg like tomatoes I mostly use bottomless pots which the plants can them root through in to the soil below ( I use the Morrison 10 for a £1 ones and cut the bottom off) - if you were growing directly in the greenhouse soil I'd be inclined to plan on swapping some of the soil out every couple of years.
Of course if you have a very large GH or PT you can rotate the crops round a bit and so try to avoid problems that way.

[hedgehogneil]

Hi Nick, thanks for the reply. How does a bottomless pot prevent changing soil? Are pests mostly likely to occur in the soil/compost in the pot rather than in the soil where the roots are?
Thanks,
Neil.

[burnie]

Never had any pest problems growing in the greenhouse soil, providing you do crop rotation, should be fine. As for soil replacement, I don't do it as such, what I do is use some of the soil in winter topping up raised beds, then add compost and manure in the greenhouse, only remove about 3 barrows full each year from a 12 x 8 Rhino.

[Scarlet]

I've got a 20x8 Rhino - I grow toms both sides every year. I grow in the ground. I take out some soil from each of the borders (not much really) like Burnie, just a few barrow fulls from each side - I find it heavy going. But when planting in I dig a hole and chuck that soil outside into a bed, then put a spade ful off compost in the hole before my plant goes in. I feed well, the ground also gets BFB and a layer of compost.

[Snadger]

I'd go for growing in bed soil every time. The problem with not growing in soil is that you lose useable growing height because of the height of the pot and the sun heats up the sides of any pots making them dry out faster.
When growing in bed soil you don't necessarily need to water plants every day (or even twice a day when using pots) so you get consistent growth and avoid the likes of blossom end rot on tomatoes.

[Scarlet]

Watering is major for me - I'm on a meter As snadger says when growing in the ground you don't have to twice a water during the hot weather. Pots are thirsty! I mulch my borders with newspapers and water into bottles dug into the ground.