Growing Blackcurrants
Growing blackcurrants for the commercial market is a precise science, and many factors must be considered to give an adequate return for the grower. As with most horticultural crops attention to detail is critical, as any omissions, however small, can cause loss in plant health and decrease in yields. The longevity of a plantation is also critical to the return on capital and so great care must be taken to ensure that the blackcurrant bush remains healthy. A frost in late April or early May can decimate the crop, losing the grower thousands of pounds value overnight.
In the following sections you will find precise details on how we grow blackcurrants commercially, including siting, best soil types, biological details of plant development, risks in growing, nutritional requirements, weed control and how we cope with prevalent pests and diseases.
Site Selection
The initial siting of the blackcurrant plantation is one of the most important factors of growing a healthy plantation. Blackcurrant flowers are easily damaged by spring frosts, consequently it is important to have a sufficient downhill slope to permit cold air to drain to lower levels, and to shelter the plantation from the NW through to NE winds. Cold air behaves like water in finding the lowest level but is slower moving. Exposed sites are avoided as strong winds during spring and summer can easily damage the bushes and strip both flowers and fruit.
Many plantations are planted adjacent to existing woodlands or hedges, but where it is necessary to provide additional shelter, windbreaks are established. Historically, species suitable for windbreaks include Alder (Red, Italian or Grey but not Common Alder) for in-field planting, and Pines, Alder or Birch for perimeter protection. Poplars, once so common, are now not used as they are very water demanding. However where possible multi-species windbreaks are now encouraged to create a wide range of habitats for wildlife.
Soil Types
Not only should a plantation be planted on a suitable site, but the soil must also be appropriate for the blackcurrant bush to flourish. Blackcurrants produce both surface & deep roots requiring well-drained and aerated soils with a good capacity to retain moisture. Soils with a high water table or imperfect drainage lie wet in winter and this will lead to the death of the deep roots and reduction in growth and yield the following season. The pH of the soil should ideally be between 6.5 and 6.8.
Any soil having a low organic matter content (organic matter is so essential for worms) may not be satisfactory regarding fertility & moisture retention and would need to be improved by ploughing in farmyard manure or crop straw before planting. Blackcurrants are tolerant of a wide variety of sites and soil types, judging by the range of locations and latitudes chosen by growers for this crop.
Soil texture, depth, drainage and moisture holding capacity are limiting factors affecting bush growth. Improvement by deep cultivation, sub-soiling, mulching & incorporation of organic manure, and attention to drainage will promote root activity and help to sustain overall bush development. Water availability is a function of soil depth & organic matter content, and any water shortage can be augmented by irrigation. Plantations on high ground tend to be cooler and receive more rainfall than those at sea level.
