raised bed on concrete patio?

[neil1280]

I came across 4 old railway sleepers, so i put them together to make a square

I was just gonna put them on my patio which is just solid concrete, would this be ok or do I need to do something to allow for drainage?

its 9 inches deep that should be adequate for most things like courgettes and peas shouldnt it?

[Potstubsdustbins]

Neil,

First take care when using old railway sleepers to preserve them they used to be soaked in creosote.

As to drainage any excess water will run away quite naturally between the sleepers and the concrete. My 2 beds are 9`-10` deep and to maximise depth of soil there are no crocks in the bottom.

Not sure about courgettes someone else will answer that for you. But my peas are in an other container that is only 9` deep and they seem to do well every year.

In the 2 big beds I grow calabrese followed by spring cabbage.

Hope this helps Colin

[taff]

courgettes should be ok, keep an eye on them in really windy weather if you have any.