Raised bed over concrete or straight into soil?

Hi,

Please excuse my naiive terminology as I'm absolutely new to this. We are impressed by our friends' home-grown vegetables tales and would love to do it in our garden, which is currently going to waste. We're about to renovate it and start fresh.

Basically, there's a rectangular 3m x 4m area in our garden we have earmarked as where we want to grow a little vegetable patch. At present, this area is concrete, and adjoins the end of our grassed area. We are getting a concrete area down the other end of our garden broken up and turfed over, so I'm open-minded towards breaking up this concrete area too.

Basically my question is, as a first-time but potentially commited and keen veg gardener:
Will it be in my best interests to:
a) build a raised bed on top of this concrete base
or
b) break up the concrete base, remove it, and grow veg directly into the earth at ground level.

Any pros, cons and brutal honesty appreciated. Would love to know what to do so we can get started. I'm willing to spend on whatever to get the best long term results.

Many thanks in advance for your help.
Alistair

 

Breaking up the concrete could be a huge job and then you don't know what is underneath, could be rubble then subsoil!

I would go for building a couple of raised beds directly on the concrete. They would need to be a reasonable depth, say 2ft and they would tend to dry out and need watering in summer but you could grow some decent crops.

I reckon optimum width is around 4ft / 1.2m so you can reach the middle from either side.

People build raised beds on the cheap with scaffold boards or decking but I would push the boat out and get some decent 6 x 2in tanalised which will not only look good but last years. We get 4m lengths for £9 from a local sawmill/timber yard, each one would make a side of 2.8m and an end 1.2m - £72 for a bed 2ft high, when you think what people spend on teles and kitchens, it's got to be good value!

 

I agree about the drainage problems.

 

I put a raised bed of sorts on concrete, drainage was the least of my problems

 

Hello,

The concrete has to go.

 

It depends what you growing though regarding drainage. And waht about the future? You dont want to have that amount of soil in the wrong place it its an issue later.

Also worms cant get through concrete!

 

Just buy a couple of tubs of brandlings from a tackle shop and pop them into the bed, you`ll soon have hundreds.

 

I have a raised bed constructed in brick on a concrete base near my greenhouse. had no problems with drainage grew potatoes last year and salad the year before.