What can I start now in an unheated greenhouse?

[mrbadexample]

as to the concrete it might be easier to just spread some gravel over it as that will make it less slippy and when the weather is hot, you can tip some water on it to raise the humidity in your GH.

Raising the humidity isn't the problem - lowering it is. I can always add more water. The problem I have is water gets in through the roof when the vents are open, through the door when that's open (all the time because I'm trying to increase airflow), and it also creeps in under the edges when it rains. Because the concrete is level, it doesn't drain away.

I live in Walsall, and the humidity in my greenhouse is close to 100% all year round because it's usually raining. This encourages botrytis which ruins my tomatoes, especially towards the end of the year.

One thing I do need to invest in is a louvred window kit to install low down opposite the door so I get more airflow that way.

[rary]

^^^^^^ it should be OK against pressure washing, as it's not too expensive you could always do it again after the wash

VC is it a wide path?

[veggiechicken]

VC is it a wide path?

I hope you're not suggesting I need one.

Its wider than in this one!!

[rary]

I hope you're not suggesting I need one.

you surely don't think that I would imply that that
But does raise an other question how much room in a greenhouse is given over for paths? As you know you older folk will need a wider path while us younger ones are more able to work in a confined space

[nickdub]

Raising the humidity isn't the problem - lowering it is. I can always add more water. The problem I have is water gets in through the roof when the vents are open, through the door when that's open (all the time because I'm trying to increase airflow), and it also creeps in under the edges when it rains. Because the concrete is level, it doesn't drain away.

I live in Walsall, and the humidity in my greenhouse is close to 100% all year round because it's usually raining. This encourages botrytis which ruins my tomatoes, especially towards the end of the year.

One thing I do need to invest in is a louvred window kit to install low down opposite the door so I get more airflow that way.

OK I'm with you - sounds like the water ingress and the impermeable floor are combing to cause most of the problem. You've obviously considered upping the ventilation, which is probably the simplest thing to try.

Not sure without looking at it what I'd try apart from that - options obviously include doing something to the floor to change the drainage, and doing something to the structure to help prevent so much rain getting in.

I think I'd hang fire with any treatment to seal the base as I can't see how that will help things.

[rary]

Raising the humidity isn't the problem - lowering it is. I can always add more water. The problem I have is water gets in through the roof when the vents are open, through the door when that's open (all the time because I'm trying to increase airflow), and it also creeps in under the edges when it rains. Because the concrete is level, it doesn't drain away.

If you have or can put electricity into your greenhouse you could run a small fan for air movement, which also gives you some frost protection as moving air can keep frost at bay

[mrbadexample]

So, here's an illustration of the problem. The floor's gone green over the last season:



When I sweep it, the sand comes away from the surface:



After washing the floor, I have a swimming pool:



When using the pressure washer it feels like being sandblasted as more fine material is stripped from the surface. The water has nowhere to drain away to.

So I need to stop the surface of the concrete breaking up, and find a way to let the water out.

The only practical solution to the drainage issue that I can think of is to put some sort of drainage system in, maybe like this: https://www.screwfix.com/p/floplast-...x-1012mm/42589

Any thoughts? It's getting on my nerves and needs sorting asap.

[Billy's lad]

If you have a tile shop near you think about a bag of floor self leveller which will seal the concrete
It looks like the concrete hasnt got enough cement in it so is breaking down

[nickdub]

I'd go with the advice above and use a bag of self-leveling screed on it, but first I'd break up or drill a 2 or 3" hole in one corner so that any water in the future can drain away

[rary]

If I had that problem I would brush it clean then make up a good concrete mix using 6mil. granite gravel or similar, and then cover existing floor with a minimum 2inch cover of the mix
Should have added rock dust (known as whin dust in this area) can be used in place of sand to give a harder mix and the mix is generally 3x3x1 that is three of gravel three ofsand/dust one of cement

[Penellype]

I agree with Rary, if water is seeping in under the edges of the greenhouse when it rains, then the floor is too low. I wouldn't have a clue how to go about raising it myself so I will leave that to those who know about these things, but water will always find the lowest point.

[mrbadexample]

The floor's just level, rather than too low.

I am really, really reluctant to think about screeding it, especially without moving the greenhouse first, and that's not happening.

Has anyone ever tried using a concrete hardener / dustproofer like this? https://www.amazon.co.uk/dp/B079P3PY...01BSZBAZ4?th=1

It seems a more practical solution, provided that it works, of course.

[veggiechicken]

Seal the outside edge of the GH to the base so that water can't seep underneath.
As Nick suggested, drill a corner out to drain the water out and stop pressure washing it!
If you know the water can't drain away, why keep introducing more.

[mrbadexample]

stop pressure washing it!

So the solution is to never clean my greenhouse again? I'm not sure that works for me.

[veggiechicken]

I didn't say that. I've never pressure washed a GH out in my life.