[lochnesslass]

i'd like to put a raised bed on some of our lock bloc if i can persude my hubby (previous owners must of had shares in the damn stuff) so how deep would the bed need to be?
i can plant root crops in another raised bed that is on ground, so it would be for likes of cabbages, brussels, lettice, turnips?, beets?
i'd love to lift the blocks but i'm not allowed 

[the Kergan]

Mine are just over 12 inches deep. Don't know of to many root veg that are more than a foot long.

[viettaclark]

Mine are 18" on soil. I would guess you'd need 9"+ on slabs. Lettuce is shallow rooting but brassicas can go down 8"+

[Ice]

I would suggest a minimum depth of 8".  It's a raised bed so you ought to select a tight headed cabbage, lettuce would also be fine.  Brassicas like sprouts, prefer to have a firm footing in the soil but I have had some success with other brassicas in just 8" of soil.

[leeks r us]

1 foot will be fine for the crops mentioned but you must watch your watering as raised beds dry out quicker as a rule than planting straight to mother earth. carrots parsnips  need to be much deeper of course but for what you are growing it should be fine.

[lochnesslass]

fantastic 
so it doesnt need to be as deep as i feared, now have to keep chpping away at hubby to make it.
i was thinking about 12'' deep anyway.
what could i not put in it, that might be easier, and i'll put these in the ground based raised bed. - i presume, carrots, parsnips, ?potatos,
oh im a happy bunny now.
just wanted to grass some more of the garden for the kids without loosing veg growing space.

[the Kergan]

I dont think carrots and parsnips would be a problem in a 12 inch raised bed. I had a very nice crop without getting forked carrots from 12 inch deep planters last year 

[Kleftiwallah]

Mine are between 12" and 2'  all made from 24" paving slabs in various sunken depths.     Cheers,     Tony.

[oldcow]

I use square foot gardening, and my raised beds are 6", as suggested by the book by Mel Bartolomew. It requires you to use a rich mix in the beds (one third mixed compost, ex. horse, chicken, green manure, one third peat, one third coarse vermiculite), but you get a huge amount of veggies and no weeding. In the last two years I grew tomatoes, courgettes, cabbages, calabrese, tenderstem, peppers, aubergines, snap peas, lettuce, spinach, bok choy, carrots (varieties that don't grow long), chillies, beets, swiss chard, green beans, all sorts of herbs, shallots, mini cucumbers, cauliflowers, arugula and a few chinese veggies!
I was amazed that stuff could grow in such a shallow bed, but he says that plants don't need to send their roots deep if they find the nutrients they need at a higher level - and it seems to be true. You will need to water more often, and you'll need deeper beds if you want to grow long carrots, parsnips etc.

[Yorkie]

The gardening expert on my local BBC show this weekend said to aim for 18" depth in order to be flexible for most veggies.

I have had many parsnips that are longer than 12", and I'm not the only one...