Gardening Articles: Edibles :: Small Fruits & Berries
by National Gardening Association Editors
Raspberries thrive in well-worked, well-fed, slightly acid soil (pH 5.5 to 6.8). Like most fruits, they crave sunlight and plenty of moisture, but adequate drainage is critical. Take the time to eliminate perennial weeds as much as possible, either by repeated tilling or by planting a cover crop a year in advance. Be sure to mix in some 10-10-10 fertilizer (1 to 2 pounds per 20 feet of row) or plenty of manure in early spring before you plant. Not even virus-free or tissue culture plants are immune to infection, so destroy any neighboring wild raspberries or blackberries (within about 300 feet) that might harbor disease.
Early spring (late winter in the South) is the best time to plant raspberries. If you're importing plants from a friend's patch (or moving plants around in your own expanding patch), spring is the time to dig them. Keep bare-root raspberry roots moist by covering them with damp peat moss or soil until planting time. Soak the roots in a bucket of water for an hour before setting plants in the garden. Set each plant in a well-watered hole that's wide enough and deep enough for the roots to spread out. Firm the soil over the roots and cover each cane an inch or two deeper than it was previously grown. Water some more. Cut each cane back to an 8-inch handle to give the roots a chance to get established. To prevent anthracnose disease in black raspberry canes, cut them right back to ground level. The handle usually dies back anyway unless conditions are perfect; it's not a problem as long as the roots are all right underneath. Red and yellow raspberries multiply by root suckers that spread rapidly in all directions; they can be confined to a hedgerow but not to rows of individual plants.
Planting Black Raspberries
Blackcaps produce no root suckers at all and propagate only by tip-layering. They can be limited easily to isolated hills without crowding neighbors. Purple raspberries can be trained to a row of discrete plants, but some do produce root suckers which can fill out a hedgerow in time. In either case, set the plants about 3 feet apart in a row. Those that sucker can be allowed to fill out a hedge no more than 2 feet wide; those that don't will stay in a single row of hills. Leave about 6 or 7 feet between rows to promote good air circulation for healthy plants and berries. You can till the aisles bare and mulch them heavily, or plant grass and keep it mowed.