Soil and Leaf Analysis

As a general recommendation, blackberry growers should follow the same soil and plant tissue testing information provided for raspberries. No calibrated soil or tissue testing system is available for blackberries.

Fertilizers

New Plantings. In most instances no fertilizer is required at planting. Once growth begins, band a complete fertilizer 30 cm (1 ft) from the transplant. Recommended rates of nutrients are given below for new and established plantings.

Established Plantings. In the second and subsequent years of growth blackberries have a low requirement for most nutrients. Usually nitrogen is the only nutrient required. Apply the nitrogen in a 1 m (3 ft) band around the plants or band half the rate down either side of the row about 40 cm (16 in) from the plant. Apply nitrogen when growth begins.

Application rates are dependent on spacing of plants. The highest application rates are set for plant spacings that give about 1600 plants per hectare.

Manure Use

Poultry manure is an effective source of nitrogen for blackberries but must be stored and spread in an environmentally responsible manner. A manure spreader designed for side delivery or band application can be used to apply poultry manure. Spread manure only once each season – broadcast and incorporated into the soil in the early spring (after February 15 and before April 15). Base application rates on a late summer soil test. Most poultry manure contains up to 12 kg/yd³ of total nitrogen. Some ammonia nitrogen is lost during application and losses are greater when manure is left on the soil surface for more than 12 hours. Poultry manure is generally very high in calcium and contains high levels of ammonia nitrogen that is readily available to plants.

Preplant application. Apply manure at a rate that does not exceed 50 kg/ha (20 kg/acre) of available nitrogen. Newly planted blackberries require low amounts of nitrogen and this rate is almost the maximum required. Applying and immediately incorporating about 5 yd³/ha (2 yd³/acre) poultry manure provides most of the nitrogen required by newly planted blackberries.

Established plantings. Apply manure at a rate that does not exceed 90 kg/ha (36 kg/acre) of available nitrogen. Established blackberries require low amounts of nitrogen and this rate is almost the maximum required. Applying and immediately incorporating about 9 yd³/ha (3.5 yd³/acre) poultry manure provides most of the nitrogen required by established blackberries.

A soil test about 3 weeks after applying manure will show if more additional nitrogen is required.