Hello John
Taking your questions in turn
1 As with anything the better the preparation the better the results will be. Get the soil as clean as possible - taking great care to get out perennial weeds especially bindweed as mentioned above. Incorporate as much organic stuff as possible particularly in the raspberry bed. Use a balanced fertilizer such as growmore or better still a high P and K one if you need to improve the nutrient levels. I also use sequestered iron on my bushes to prevent chlorosis but this may just because my soil is rather light.
2 I've had a TwoWests standard fruit cage for many years and it has given very good service.
http://www.twowests.co.uk/TwoWestsSite/product/FCS6.htmThe tubing is aluminium, the corner joints are nylon and the whole thing is put together by simply and easily knocking the joints onto the tubing with a wooden mallet. This system like many others is based on a 6 ft spacing of uprights but some use other lengths eg 8ft. Years ago I tried various DIY poles and rods without much success. With this TW system you can either buy the complete kit or get the poles and joints separately if say you've already got some netting. Its easy to modify as the alloy tubing can be neatly cut to any size with a plumbers pipe cutting tool (TW suggest a hacksaw but it is not that easy to get a clean cut).
3 It doesn't matter whether you plant first or put cage up first. It's very important to decide what cage you're going to get though so that you get the plant spacing correct. Allow room inside your cage to move around for picking taking into account the final sizes of your bushes.
If you use a 6 ft system this would be a good plan (poles in red) if you can make your cage 12ft x 12ft rather than 10ft square:
O----------O----------O— 7 raspberries —
O----------O----------O— 3 fruit bushes —
O----------O----------ORaspberries are spaced at 18in so 7 in a row allows room to get round the end of the rows and for wire supports. Fruit bushes are normally 3ft apart so 3 in row will give you just enough room to get round. If you have to use a 10ft square cage use the same plan but with only 6 raspberries in the row.
Now is the time to plant your bushes but time is running out.
If you choose summer fruiting raspberries (in my opinion these are by far the best) you won't be picking any fruit until next year. Don't expect your fruit bushes to give you much fruit this year.
Hope all this is of some use
John
PS Raspberries are such a versatile (and delicious fruit) I've suggested 6 or 7 rather than the 3 you suggested. They freeze well and make superb jam!
) and thought I might turn part of it into a soft fruit growing area, instead of just grassing it over. I've never grown soft fruits before, but assume that after they're planted the work involved is basically pruning and spraying. (?). The area is 10ft x 10ft and is well-worked and fertilised soil that has been used to grow everything from pots. to sprouts.
