So, I've been reading Mel's book lately. I'd like to grow raspberries using some of the techniques in Mel's book.
I don't want to grow them in with lots of other things since raspberries can be so invasive. I want to make a 2 foot wide bed (not sure how long I want to make it) and line the bottom of my box with weed block. All this will do 2 things for me. First, I have very heavy clay soil. Using the raised beds will get the plants up out of this clay and get them draining better.
Next, it should keep them from getting out into the yard. I want to do this not only to keep the lawn free of raspberry canes, but also to prevent any problems with my septic system as the only place I have available to plant is right next to the drain field. I'm being very careful with the septic system because I have that heavy, clay soil that I've been talking about. I know that previous owners of this property have had problems with good percolation because the tank shows signs of raised levels at some point in the past. The grey water has also been separated out in the plumbing and goes to it's own place. Probably going to use the grey water to be more useful than just putting it in a hole in the ground sometime.
As far as bed height goes, I'm not sure if I should go with just 6" or if I should go ahead and do 12". I know that raspberries are fairly shallow rooted so I wouldn't think that depth would be a problem. I asked on a different forum and they seemed to think I would need a good 3' of good soil. I'd like to get away with no more than 12" as I would be using the weed block to keep everything in.