Cultivation

Cultivating fall raspberries is custom work. We at Advanced Berry Breeding know that better than anyone else. A good crop is the result of the right variety, the proper planting distance and exceptional management, as well as many other factors. We support our clients in this by offering advice, some of which we discuss here.

We will just give a general description of raspberry cultivation. Since the climate and local growing conditions differ significantly for each concern, we advise growers to experiment and test on their own in order to further develop and optimise their own cultivation.

The right cultivation system

Raspberry cultivation is undergoing considerable development and is shifting more and more from summer to fall varieties. Growers frequently prefer fall raspberries because they bear fruit already in the first year. Another trend is cultivation systems for raspberry production outside the main season. Advanced Berry Breeding’s varieties have an important role in this.

We distinguish between cultivation systems: ‘double cropping’ and ‘primocane cultivation’. Double cropping, though, is the most common system, with a wide range of possibilities: outdoor, greenhouse and tunnel cultivation, various plant types and diverse pruning systems. Combining cultivation systems creates an extended supply period for raspberries.

Whichever parent material you choose, Advanced Berry Breeding’s varieties generate robust plants. They require little support, needing only to be attached to a few horizontal wires. Using netting is unnecessary, and consequently harvest is quicker and production costs are lower.

Double cropping from A to Z

Double cropping begins with fresh plug plants, tray plants or root balls. The latter two plant types are in dormancy and have to send up new shoots from the root.

This form of cultivation with fresh plug plants typically involves a plant density of three plants per meter. Depending on variety and cultivation system, we retain one or two lower laterals. These laterals and the main shoot are trained toward the perimeter of the row so that the leaf receives maximum light.

Double cropping with dormant plants, or even plants with just a root ball, can be set up using chilled plug plants or tray plants. After planting, the plant makes new shoots from the root. A selection follows, and the smaller shoots are pruned for the most suitable plant density.

Preparation for next season

With continuous cultivation, the grower has the choice of ‘pruning back the canes’ or ‘mowing down’ after harvest.

When pruning back the canes, we cut them back to 2 or 3 leaves below the lowest flower cluster. The remaining nodes may not be flowering buds, and form new laterals. We usually get good results with 12 to 15 laterals per cane, and 40 to 60 laterals per linear meter. That way we prevent diminished fruit quality and too dense a crop, thereby improving picking speed.

In mowing down the plant is cut down to the ground. In response the plants produce many more shoots. These are reduced with a number of prunings: the vigorous shoots are kept and the weaker canes are removed. More and more growers prefer to replant due to the high costs of pruning.

End of harvest

The plants overwinter in a cooler or even outdoors in areas with mild winters. After planting the plants go into bloom on new laterals. Harvest is postponed to a later time by keeping the plants in the cooler longer.

If the plants do not go into dormancy on their own at the end of harvest due to too high a temperature, remove the leaves. If the plants are in pots, it is possible to cool them at -1oC. The Advanced Berry Breeding varieties require very little cold to do well in the next season.

Towards year-round production

In some periods outside of the main season the prices for raspberries are relatively high. In Northern Europe we use cooled plants grown in pots in the summer in order to provide fruit during this period as well. Growers use ‘long canes’, rooting blocks or plants that are pruned back after the primocane harvest.

In North-western Europe long canes are usually planted between mid-April and the end of May. A series of such crops creates a more continuous supply of raspberries. Growers in Southern Europe commonly set out long canes in the spring for an early production.

But more variables are possible, such as the right choice of variety. Some varieties, like our Shani and Imara® varieties in Spain, are more appropriate for harvest in the winter, with very little light and at low temperatures. We sometimes grow other varieties in the Netherlands under LED lights in the winter months. And in warmer climates the planting dates are adapted to the growing and weather conditions. This way growers in Southern Europe sometimes have five crops in two years.

Greenhouse cultivation

Plug plants are potted in April in the greenhouse. About six weeks later the plants are moved outdoors to a tray field and are returned to the greenhouse in July. Harvest starts in August and extends late into autumn. After pruning the plants, the lateral shoots sprout in the following spring, providing a new harvest between mid-April and mid-June.

Planning the harvest

By keeping the plants uniform and utilising good cultivation and pruning techniques, the raspberry harvest lasts approximately six weeks. This offers the potential to plan well for a harvest in periods with typically better prices.