In article rLg3c.2544$m56.2263@newsfe1-win,
(Andy Hunt) wrote:

It is of the nature of raspberry canes to drink quite a lot of water and
spread horizontally putting up lots more canes. I would suggest a soil
surface area of around 0.25 sqm per planted cane. Depth is less of an
issue as raspberries are shallow rooting.

Steve Harris - Cheltenham - Real address steve AT netservs DOT com
A useful bit of gardening software at http://www.netservs.com/garden/