raised beds for veg

[sphil]

I want to build some raised beds for vegetables on an exisiting patio. Can I just build the beds straight onto the paving slabs? I'm sure i read somewhere that this is possible as long as you leave drainage holes at the bottom of the vertical walls of the beds.

How high would the walls need to be for optimal veg growing?

I am really inexperienced, so I don't feel that I can give much advice here.
Surely you need to consider what you are going to grow. When I grew potatoes they were quite deep. I have a bit of concrete in a small patch of my bed about a spade depth down and it has been a pain.
I know a lot can be planted in pots. Have you thought of that instead?

also pretty inexperienced but;

depends if youre growing root veg or topofsoil things like cabbages, i would think (depth)

a combination of potato pots/bags, with staggered planting to stretch out harvest time and a raised bed of about, i dunno, 20-30cms for cabbages, leeks, beans maybe... toms are good in growbags.

We put two sleepers on top of each other so I guess about 1 1/2 ft deep? But we have earth under ours.

sixofone have you lined the bed, or do you just grow flowers in it? Real sleepers are supposed to exude toxic stuff and not recomended for growing veg in/by. Some people reckon you shouldn't use any treated wood in fact.

We have these straight onto our patio. They drain beautifully through some drilled holes.

Raised Beds

Thanks everyone
Problem is solved as we've decided to site the beds beside the patio on soil. I found a company on e-bay that makes wooden beds to order - DH reckons he'd be hard pressed to buy the materials more cheaply!

Sphil

Would you mind posting a link to the ebay site? I'm interested in wooden beds too at the moment, but completely hopeless at making anything like that. Thanks

Hi snorkle, they are not 'old' sleepers (i.e. the ones with toxic chemicals in, but instead sort of bare wood ones. We got them from a local landscaping centre, think we paid £80 for 8 of them inc delivery.

oh that sounds good sixofone, I'm glad. It would be a shame to grow your own veg and accidently poison yourself in the process.

Sorry Corriewatcher - haven't looked at this thread for a few days. here you go

You need to scroll down as they do an off-line service. Not sure if they have any more on e-bay itself.