Raspberries are a worthwhile soft fruit on the allotment – depending on the cultivar a single plant of usually six canes can produce about 1-2 kilos of fruit in a space as small as 40 cm (16 inches) square and will give good yields for typically 10 years.
Raspberries need fertile, slightly acidic, moisture-retentive soil. They grow well in partial shade (but don’t do this with autumn fruiting raspberries which you might want to have as double cropping).
- Raspberries require post and wire support.
- Fruiting crops like lots of fertiliser – use bonemeal in spring.
- Water well in dry spells.
- Harvest June to October.
There are autumn-fruiting types – these fruit on this year’s stems. A double fence is best for autumn fruiting raspberries – space two rows of posts 20-24 inches (50-60cm) apart, and stretch wire horizontally across. Use wire as cross ties every 2 feet.
- Autumn fruiting raspberries flower and fruit on growth made in the current season, typically from August to October. This is known as primocanes.
- Prune all canes to ground level in February, leaving no stubs.
- Over the summer growing season select the strongest canes, thinning out the weakest canes if overcrowded, and remove suckers growing away from the rows.
Double Crops from Autumn Raspberries: After fruiting in autumn, remove the top 2 feet (60cm) of stems. In spring, stems branch, producing flowers on sideshoots, followed by a small crop in June. Once fruited, cut to the ground these canes. Plants continue to grow new canes in spring, with the main crop delayed to September. When you do this it is said that the early crop is low but with the later harvest the overall yield is higher. But note well: double cropping is only successful in a very fertile, sunny spot.
There are also traditional summer cropping raspberries which fruit on last year’s canes. These are best trained with a system of single fence wires and posts (or against fences).
- Summer fruiting raspberries produce flowers and fruit on one year old canes.
- Summer fruiting cultivars tend to produce a flush of fruit over a 2 to 3 week period from late June to August and flower on canes produced in the previous year (floricanes).
- Generally speaking summer fruiting types produce higher yields of fruit.
- Prune fruited canes of summer cropping raspberries after harvest right down to ground level, avoiding leaving a stub.
- Thin out new growth to leave one cane every 4-6 inches, and cut out excess growth at ground level. Tie-in the new canes for support.
- Remember not to leave stubs which can let in disease.
- As it grows, support strong canes and cut out weaker ones at ground level.
- Through the season loop long canes over the top wire and tie in.
- In February, trim these long canes to a bud 4 inches (10cm) above the top wire.