In message , Iamhanuman
writes

I have decided to purchase raised beds to start my gardening year.
I'm a novice but have heard and read good things about raised beds.
I was going to buy the kits from Dobies which are 1mx1m and 10in in
height, but a brochure in a recent 'Grow Your Own' from Harrod has kits
which are 1mx1m and 6in in height for nearly half the price.

Can anyone tell me whether that extra 4 inches matters, and no smutty
answers please?

I don't know what you plan to pay nor how much space you have for the
beds but I suspect you can make a raised bed for much less than you will
be paying. I have 5 measuring c. 14 ft X 4ft each 14 ins high. I used
old joists left over from some building work we had done. After giving
them a coat of friendly preservative they were set up very easily and
have lasted 7 years without any rotting or damage. And the whole thing
cost me less than a fiver. But I realise that timber of that type is
expensive however I'm sure that you should be able to find a friendly
builder who is demolishing or extending an existing building who would
part with the old wood - maybe for nothing if you take it away.

I recognise that this may not convenient or what you want so - in answer
to your actual question (finally!) I would make raised beds as deep as
possible (within reason) ...i.e. 10ins rather than 6ins. Of course it
depends what you plan to grow in them.... root vegetables (spuds,
parsnips, many carrots etc.) would appreciate a decent depth of soil.

Regardless ... good luck! You'll find it rewarding.
--
Gopher .... I know my place!