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Drainage for Plant Box
Michael Schmitt
Posts: 5
Hello,
I've created a wooden flower box to sit on top of a concrete base. I'm worried about the drainage as the concrete base is too thick to put drainage holes into, to allow excess water out.
I was thinking of putting gravel followed by a fine layer of sand onto and putting a rubber tube through one side of the wooden box to allow the excess water to drain out. Or could I get away with not allowing it to drain out?
all suggestions welcomed.
0
Posts
I suggest drilling holes in the bottom of the box and standing it on something which will raise it about an inch or so above the concrete. The only problem might be dirty water running out over the concrete, but if you line the bottom of the box with a layer of porous weed membrane, that should act as a dirt filter.
Hi Michael - you have to have drainage. The best way with this type of planter is to create a false bottom, ie - put the base of the container about an inch or two higher leaving a gap between the four sides and the concrete base. Drill plenty of holes in it and you'll have no problem.
I live in west central Scotland - not where that photo is...
Snap Bob - more or less! I've done this with boxes on top of my fence - the base sits on battens attached to sides of the box.
I use the weed fabric too! Great minds
I live in west central Scotland - not where that photo is...
As`always Fairygirl!
Perhaps it's like a kind of convergent evolution - we gardeners have the same problems and so come up with similar solutions? 
The flower pot is going to be set beside a sloped paving ramp, and has a wide concrete base, and there is concrete gravel board behind it. So back and bottom are concrete. there is drainage access on the right side, but no direct access to drainage soil on the left. The concrete seems to be very thick and I do not have access to a kanga and wouldn't want to weaken the concrete foundation by trying to break this up.
hence why I was wondering if a hose tube put through the left side going in a few inches would help provide drainage.
I managed to drill through the concrete on the left hand side. The hole is about 4" in diametre, so I am hoping this will be enough to drain the box. The box is approx 220 litres.
Do i need to fill this hole with large pebbles or sand to help the drainage and to stop the soil from going down the drainage hole?
Hi Michael, I may just be thick but I'm having difficulty visualising the container
A pic would be helpful
I think you'll be ok with that but you'd have to ensure that excess water can run to that end to safely drain away. Better to drill holes down at the bottom of the timber at the right hand end, as suggested by Welshonion. That should resolve that issue.
Yes - you'll need to use something to cover the hole. It's hard to suggest anything without seeing it, but some of the landscape fabric (or similar) with a couple of larger stones to hold it in place will allow water out but not the soil/compost. Just make sure the stones still leave enough of a gap for that and for compost in and around them for plant roots.
I live in west central Scotland - not where that photo is...