Site and soil
Ideally choose a sunny position sheltered from cold winds and late frosts that can damage the flowers in spring, though modern cultivars show better cold resistance. Blackcurrants can be grown in light shade.
Blackcurrants will tolerate a wide range of soils, but being heavy feeders they prefer moisture-retentive fertile soils that are reasonably well-drained. They can cope with slightly impaired drainage.
Blackcurrants crop best on strong young growth made the previous season, so they are usually grown as a stooled multi-stemmed bush. This involves annual hard pruning of older growth to encourage strong young shoots growing from ground level.
Standard-trained blackcurrants are useful if space is limited. Standards or half-standards are "top worked" bushes – grafted on rootstocks (usually Ribes aureum) with 60cm-1m (2-3¼ft) clear ‘leg’.
Remove all perennial weeds, then incorporate into the planting area 5cm (2in) dressing of bulky organic material, such as manure based soil conditioner or garden compost. This is particularly important on light soils. Just before planting, fork in a compound fertiliser such as Growmore at 85g per m² (3oz per sq yd).
Buy two-year-old bushes container grown or bare-root FPCS certified stock (The Fruit Propagation Certification Scheme).
Plant bare root plants between October and March, but it is generally best to avoid planting in the middle of winter when the soil is either wet or frozen. Container-grown plants can be planted almost any time, but need regular watering during the dry periods.
Plant both container-grown and bare-root bush plants 5cm (2in) deeper than previously planted; look for the nursery soil mark at base. This will encourage strong shoot development from the base. Plant standards at the same soil depth as previously grown.
Space plants 1.5-1.8m (5-6ft) apart, using the wider spacing for vigorous cultivars.
Pruning at planting
When planting in autumn to early spring cut all shoots back to 2.5cm (1in) above soil level in order to achieve strong growth from the base. Though this seems extreme and the first year’s fruit is lost, this will be beneficial in the long term. On well-developed plants you can retain half of the shoots that will give a small crop. Do not prune container-grown plants hard on planting if planted later in the season when they are actively growing.
Standards do not require hard pruning after planting.
Blackcurrants generally do not perform well in containers long term due to the growing habit and size of the plants. However, underperforming containerised plants can recover if planted out into open ground. More compact cultivars such as ‘Ben Sarek’ and ‘Ben Gairn’ are better suited for containers.
Choose a sizeable container about 45cm (18in) wide and deep. Use a soil based compost such as John Innes No. 3, improved with 20-30% by volume multipurpose compost and 10% perlite/sharp-sand/horticultural grit. Alternatively, use peat-free multipurpose compost mixed with about 20% perlite/sharp-sand/horticultural grit.
Mix in a slow-release fertiliser or liquid feed during the summer months. Annually top dress with fresh potting compost. Re-pot after 3-4 years in late winter or early spring. Remove some of the old compost and trim some larger roots on the outside of the rootball.
Feeding and mulching
Feed annually with a general fertilizer, such as Growmore at 100g per square metre (3oz per sq yd) in spring. Weak plants can benefit from an additional high nitrogen feed at 25g per m² (¾oz per sq yd) of ammonium sulphate. Follow feeding with mulching around the base, using a 5cm (2 in) deep layer of organic mulch such as manure-based soil conditioner or garden compost.
Water well in dry weather at ground level rather than overhead. Avoid heavy watering as fruit ripens to prevent skins splitting.
Protect bushes in flower by covering them with fleece or cloth on nights when frost is forecast.