Site Selection

With good soil, climatic and management conditions, raspberry plantings can remain productive for 10 or more years. However nematodes, root rot or raspberry bushy dwarf virus (RBDV) may greatly shorten a planting’s productive life.

Consider the following when selecting and preparing sites for raspberries.

Soil

Raspberries grow best on loam or sandy-loam soils that are 60 to 120 cm (2 to 4 ft) deep and well-drained. A soil pH of 5.8 to 6.5 is optimum. Avoid planting on poorly drained, heavy soils or soils with a hardpan that will prevent good drainage. This will cause root rot problems and result in poor yields and a short planting life. Raspberries can be grown on sandy and gravelly soils but will require careful irrigation and nutrient management, as these soils do not hold water and nutrients well. Drip irrigation is particularly beneficial on these soils.

Drainage

Raspberries cannot tolerate flooding or waterlogged soils, especially when the plants are actively growing. The roots will rot and the plants may die. A subsurface drainage system is necessary for fields with poor natural drainage. Surface drainage, provided by the slope of fields or raised beds, also helps to reduce the risk of root rot. Seed fall cereal cover crops to prevent soil erosion on hilly sites; and plant grass on drives, headlands, and in areas where water runs in the field. Refer to the BCAGRI “Soil Management Handbook for the Fraser Valley” at www.agf.gov.bc.ca/resmgmt/publist/600Series/610000-1_Soil_Mgmt_Handbook_FraserValley.pdf and the B.C. Agricultural Drainage Manual at www.al.gov.bc.ca/resmgmt/publist/500Series/525500-1.pdf.

Irrigation

The root system of raspberries extends to a depth of about 1.2 m (4 ft). However, most of the active roots are in the upper 30 cm (1 ft) of soil. Thus, irrigation is essential for consistently high yields. Especially critical periods for irrigation are during the year of planting and, once established, from flowering to harvest. Manage irrigation carefully. Overwatering may result in nutrient leaching and encourage root rot. Too little irrigation or too long a period between irrigations will cause moisture stress resulting in small berries and reduced yields. Drip irrigation provides uniform continuous moisture to the crop and can help maximize yields. Refer to the section "Water Management" for information on water quality.

Rotation

Crop rotation is a sound agricultural principle that should be followed whenever practical. If raspberries are grown repeatedly in the same field for many years, root rots, insect pests and resistant weeds tend to increase. When this occurs, raspberry yields decline and plantings need to be replaced more frequently. Whenever possible, avoid growing raspberries in fields where strawberries, potatoes, peppers or tomatoes were grown in the previous four or five years as these crops are affected by similar diseases.

Site Preparation

This is a critical step to successful planting. Start to prepare the field the year before planting. Consider the following:

Nematode Control

Sample the soil in April and have a laboratory check for nematodes to determine if soil fumigation is required. If fumigation is needed, prepare the site for an early fall fumigation. To do this, control all weeds and deep cultivate the soil (see “Nematodes”).

Wireworm Control

Check for wireworms, especially in sites previously in sod, and plan for control (see “Wireworms” below and in “General Berry Pests”).

Weed Control

Control established perennial weeds such as quackgrass, horsetail, curled dock and Canada thistle before planting.

Cover Cropping

Plant a fall cereal cover crop the year before planting to add organic matter, control weeds and improve the soil drainage. Seed before September 15 to make sure crop is well-established before growth slows down in the late fall. In the spring disc the cover crop in time for it to decompose before planting.

Manure and Compost

Manure and compost add organic matter to the soil. They are also valuable sources of nitrogen, phosphorus, potassium, calcium and several micro-nutrients which are required by raspberries. Avoid heavy manure applications as this could injure new plants and increase the risk of polluting groundwater. Use of properly composted manure is preferred.

Apply manure or compost in the spring (February 15 to April 15) at least one week before planting. Be sure to consider the nutrients in the manure or compost when determining the fertilizer requirements.

Poultry manure is commonly used. Spread manure (broadcast and incorporated into the soil) in the spring before planting at rates according to crop need. Refer to Nutrient Management below for recommended rates.

Compost can be applied at slightly higher rates than those for poultry manure. An analysis of the nitrogen and salt content of the compost is recommended. Compost releases nitrogen more slowly to the crop than poultry manure.

Soil pH

Raspberries do best in a soil that is slightly acid to neutral, with a pH range of 5.8 to 6.5. Poor growth and yields often occur when the pH is outside this range. Check and adjust soil pH before planting and every 3 to 4 years after planting. When the soil pH is 5.5, it can be raised by adding ground limestone at 2 to 4 tonne/ha (1 to 2 ton/acre) depending on soil type. Broadcast and disk in lime either in the fall prior to fumigation or cover crop planting, or in the spring before planting. To lower the pH, refer to the general nutrient management section in this guide.

Nutrients

Soil analysis is the best way to determine the nutrient requirements for a new planting. Take soil samples in the fall before planting so any needed amendments can be added as the field is prepared. Refer to the nutrient management section below for sampling procedures and application rates. Base the spring fertilizer application on the results of the soil test. Include the nutrient content of any manure or compost used when determining the amount of fertilizer to apply.

Incorporate base fertilizer into the bed before planting. Subsequent applications can be broadcast over the surface of the bed or applied in bands 30 cm (1 ft) away from the row and 10 cm (4 in) below the soil surface on both sides of the row. Nitrogen rate should not exceed 75 kg/ha in the year of planting. Also refer to the nutrient management section below.

Planting

Purchase certified plants to reduce the risk of introducing nematodes, viruses, root rot and other diseases into the field.

Plant early in the spring (March to early April) for best establishment and early yields.

Plant as soon as possible after the plants are removed from storage. Plant 1 to 2 plants at the desired spacing taking care not to set the plants deeper than they grew in the nursery.

Dormant root cuttings can also be used. Use about 60 g (2 oz) of random length cuttings per hill and plant about 5 cm (2 in) deep.

Do not let the plants or root cuttings dry out at any stage of the planting process. Irrigation is essential for late plantings when weather is warm and dry.

Most machine harvested raspberries are grown on raised beds which are made at time of planting. Raised beds provide a better drained root zone which reduces the incidence of root rot. They also allow the catcher plates of the mechanical harvester to fit closer to the crown resulting in better fruit recovery.

Spacing

Raspberries are grown in hills with a spacing of 75 cm (2.5 ft) between the plants. Row spacing depends upon the plant vigour, and the cultivating and harvesting equipment. Most varieties are generally planted in rows 3 m (10 ft) apart, requiring 4,305 plants/ha (1,742 plants/acre). However, where narrow machinery and upright varieties are used, a row spacing of 2.7 m (9 ft) may be used, which requires 4,784 plants/ha (1,936 plants/acre).

Training

Install post and wire trellises in the spring after the plants start to grow. The posts should be from 6 to 9 m (20 to 30 ft) apart on flat ground, depending upon the diameter of the posts used. Thus, 358 to 536 posts/ha are required (145 to 216 posts/acre). Closer spacing is required on rolling ground. Anchor or brace the end posts. The trellis system for mechanical harvest usually consists of one heavy wire per row to support the fruiting canes plus 2 lighter wires (12 to 14 gauge) to control the new canes.