Hello here's how my grandad use to plant raspcanes we dug a trench 18 inches wide a spade and a bit deep crumbled it out,put 4 inches of well rotted muck in the bottom,then replaced the soil leaving it 6 inches from the top with a mound down the centre as if browning asparagus then we went through the rasp bed and dug out all the new canes that weren't in the row and planted them in the new trench covering them well with soil,you can still do this with the old ones you have check for Violet big bud as this can destroy the canes,and mulch with plenty of organic material as they are hungry feeders jezza