Debbie Ornquist
Plant raspberries in May once the soil is workable. Space plants 2 to 3 feet apart in the rows. Some fall-bearing raspberries can be planted at 1.5-foot spacing and produce higher yields. The plants spread quickly after the planting year by putting up more canes, rapidly filling in the space of the rows.
Row centers should be at least 6.5 to 8 feet apart. Once the canes grow and fill in the rows, the foliage and fruiting laterals encroach on the walking aisles. It is important to leave abundant space between rows to enable walking and harvesting. If growing raspberries in a high tunnel, leave enough space between the edge rows and the wall of the tunnels to harvest from both sides of the plants.
Raspberry plants are usually sold as dormant bare-root plants. These have a small root system and several inches of a cane with live dormant buds. Occasionally, nurseries sell raspberry plants as small plugs with actively growing leaves and roots If bare-root plants cannot be planted immediately after they are delivered, store them in a refrigerated space and keep the roots moist and wrapped. Prepare the soil by tilling the rows until the soil is easily workable. If possible, leave the aisles nontilled to preserve the ground cover and prevent erosion. If you till the aisles, plant a cover crop or turf seed as soon as possible to reduce erosion Dig a shallow trench down the length of the row. Lay the roots of the bare-root plants horizontally in the trenches, with the cane stub poking out of the soil surface. Backfill the trenches to cover the roots. The roots should be covered in several inches of soil so that they remain covered when the soil settles, but they do not need to be very deep. The nurseries typically provide planting instructions as well.
Do not let the soil dry out between digging the trench and planting. You can use transplanter implements to increase the efficiency and success of planting. Water immediately after planting.
Plant plug plants as soon as possible after receiving them. Prepare the soil by tilling the rows until the soil is easily workable. If possible, leave the aisles non-tilled to preserve the ground cover and prevent erosion. If you till the aisles, plant a cover crop or turf seed as soon as possible to reduce erosion. Using a transplanter or hand tools, create individual holes just slightly deeper than the length of the soil plug.
When planted, the entire root system should be below the soil and the leaves and stem aboveground, similarly to strawberry and vegetable plugs. Water immediately after planting.
The aisles can be managed with permanent ground cover vegetation, mulch, or landscape fabric. Landscape fabric is the most appropriate material to use in aisles in high tunnels.
It is best to keep the rows bare with no mulch, to promote cane emergence and prevent overly wet soil. If mulch is used, be careful not to overwater. Control weeds in the rows prior to planting and keep them weeded while the plants establish. More information on raspberry growing can be found on MN Extension Gardening website.
