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Raspberry

Rubus idaeus

Key Points

  • Generally a high-value, quick return crop in a sheltered situation.
  • Plants require winter chilling to maximise yields.
  • Long picking season.
  • Suitable varieties available for most areas of N.Z.
  • Needs careful management to produce high quality fruit.

Climate

Temperature

A warm, but not baking hot summer, and cool, but not freezing spring is ideal. Cooler temperatures at the onset of autumn promotes the initiation of flower buds for varieties that fruit on second-year wood.

Frost Tolerance

Low-lying, severely frost-prone sites are not suitable as both flowers and fruit are suceptible to a late spring freeze and premature frosts can reduce the yield from autumn-fruiting varieties.

Chill Hours

To achieve worthwhile crops raspberries need at least 400-500 hours of winter chilling at temperatures below 7°C and can be grown successfully in all but the very warmest parts of N.Z.

NZ climate charts
You can read more about NZ's Cold Hardiness and Climate Zone here

Wind/Shelter

Good shelter is vital as strong winds can damage fruit, foliage and canes but this must be balanced with the need for air movement to reduce the humidity that can promote fungal diseases and fruit rot. Estabishing live shelter belts before planting will help to filter the wind whilst still allowing good air circulation and providing the added bonus of reduced soil moisture loss during dry spells

Sunshine Hours

Most areas of N.Z receive more than adequate sunshine for raspberry production. Excessive heat and glaring sun can reduce yields by stunting growth and scorching ripe fruit however these problems can be alleviated to some extent by judicious irrigation and the provision of live shelterbelts to filter drying winds.

Rainfall

The best scenario for raspberries throughout the growing season would be adequate moisture at the roots with dry foliage, flowers and fruit. They require large amounts of available moisture through summer and if natural rainfall is insufficient to satisfy this need, irrigation is a must.

Soil Requirements

Soil Type

Raspberries produce a vigorous, fibrous root system, almost 75% of which is generally concentrated into the soil's top 45cm. They do best in a well-drained, highly fertile sandy loam with good levels of organic matter to aid moisture retention through dry periods.

Very light and stoney soils with poor moisture retention are generally unsuitable for commercial raspberry production even when there is access to efficient artificial irrigation.

Drainage

Good drainage is essential for commercial raspberry production as they are extremely sensitive to poor soil aeration and consequently suffer badly during prolonged periods of water-logged soil conditions. Heavy, wet clays and low-lying sites that are prone to flooding are generally unsuitable as bramble roots are susceptible to fungal attack and root rots when starved of oxygen.

pH & Soil Testing

An initial soil test should be taken at the earliest possible opportunity to establish the base nutrient and pH levels and to establish if any corrective treatments are required. Raspberries are fairly accomodating to pH readings anywhere between 5.5 - 6.5.

Spacing

The prolific suckering habit of raspberries dictates that they are commonly grown as a narrow hedge supported by light posts and wires. Plant spacing within the row can vary between 50cm or less, up to 1m to facilitate the development of productive stools formed from strong basal suckers. Close spacing may result in rapid development of the hedge with higher yields in the first picking season, but this advantage is offset by the increased planting costs and any benefit gained generally disappears by year two. The distance between rows is dependant on the machinery and management practices used but is usually 2.5m to 3m.

Crop Establishment

Selecting Varieties

Points to consider include location, climate, the availability of labour and machinery, end-use and your potential markets for the fruit. Be aware also that some varieties attract plant-right royalty fees and/or non-propagation agreements. See our list of varieties for more information.

Planting Time

Autumn/early winter is the preferred planting time but we can supply strong plants in 7cm tubes either in full growth or dormant to suit your needs.

Cultivation

Site preparation should commence up to 12 months prior to planting time to ensure that perennial weeds are eliminated and any drainage issues are resolved. Sub-soiling should be considered to further improve drainage and encourage deeper rooting. Planting strips should be worked to a fine tilth to provide ease of planting and to encourage rapid establishment of young plants.

Fertiliser

Any nutrient deficiencies or necessary pH adjustments indicated by the initial soil test should be corrected by incorporating suitable applications at least 6 months prior to planting. Usually, if this is done, no further fertiliser needs to be added at planting time.

Irrigation

Irrigation may not be necessary in autumn/winter but during dry spells sufficient water should be applied to thoroughly wet and settle the soil immediately after planting.

Tips

Knocking out plants from tubes and packing them into trays will speed planting operations in the field but take care that the roots are protected from the sun and are never allowed to dry out. Plant firmly and make sure that the roots are well covered with soil.

Crop Maintenance

Fertiliser

Nutrients will need to be topped up annually with N-P-K fertiliser applications based on orchard performance, plant appearance and the quantity of fruit harvested. Further soil testing may be required to identify specific nutrient deficiencies.

Irrigation

Maintaining adequate soil moisture levels from flowering, right through to the end of harvest, is essential to maximise yields so regular monitoring is needed to anticipate depletion and to minimise potential plant stress. Good management skills are required to achieve the balance between too little and excessive irrigation as too much water can also create problems.

Where sprinklers are used, they need to be raised above the top of the foliage to allow even distribution. These watering systems have the advantage of being able to be used for frost protection if required.

Drip irrigation is suited to raspberry production because it delivers water directly to the roots whilst leaving foliage and fruit dry but, again, careful monitoring is required to ensure that system is working efficiently.

Pest & Disease Control

A handful of insect pests can be particularly troublesome and raspberries even have their very own Raspberry bud moth, the larvae of which can cause damage to canes, buds and fruit. Leafrollers, bronze beetles and leaf hoppers may damage foliage while grass grub larvae prefer the roots and mites can suck the life out of the plants in summer.

Most of the fungal diseases that may affect raspberries manifest themselves where the drainage is inefficent and/or at times of high humidity. Probably the most significant are Botrytis or grey mould that gains access through dead and damaged tissue and can affect all above ground growth (including those precious berries) and 'dryberry' (downy mildew) that can damage the whole plant and may rapidly infect a large percentage of fruit during excessively wet conditions.

Good orchard hygiene can do much to minimise the risks but the efficient control of pests and diseases is particularly crucial where markets demand completely blemish-free fruit. Many growers rely on a compehensive agri-chemical spray program for control. Whether or not to apply chemical control is a decision for the individual grower to make but here at Tharfield we use an I.P.M Services (2009) Ltd integrated pest management program that requires us to regularly monitor our crops, to maintain high standards of nursery hygiene and, where appropriate, to make efficient use of predator insects in order to minimise the need for chemical controls.

Weed Control

Troublesome perennial weeds should be eradicated prior to planting as raspberries may be sensitive to the herbicides that need to be used. There may even be differences in the susceptibilty of different cultivars and plants can respond differently depending on age and the prevailing conditions at the time. Things change constantly in the world of agri-chemicals so seek advice from your horticultural advisor before applying any herbicides around your crop.

Regular mowing of grass strips or over-all mechanical cultivation can be used to control weeds and to restrict the growth of suckers between the rows but hand cultivation within the rows becomes increasingly difficult as the plants spread to form a continuous hedge.

Bird Control

Strangely, birds do not appear to be a major problem with these delicious fruits.

Pollination

Bees, honey, bumble and wild, are responsible for most of the pollination and, because raspberry pollen cannot be transferred by wind, a large, active bee population is needed throughout the flowering period. This may necessitate the introduction of up to 5 hives per hectare to ensure efficient pollination. As raspberries are self-fertile good fruit set can be expected from a single cultivar planted in isolation.

Harvest & Handling

Picking

Some raspberries for processing may be machine harvested but high quality berries for the fresh fruit market must be hand-picked . Picking is usually carried out on a daily basis, weather permitting, to ensure that the ripeness of the fruit suits the market for which it is intended.

Ideally, picking is completed when the fruit is dry but before the heat of the day affects both the fruit and the pickers.

Post Harvest

So many factors can influence yields from commercial raspberry production that it would be misleading to indicate probable yields. See our individual varieties for information about expected fruit set, size and productivity.

Expected Yield

We supply strong, well-rooted raspberries in 7cm tubes and often have stocks of some varieties, over and above our contracted orders, available ex nursery. These plants, however, are sold on a 'first come first served' basis and we can never guarantee to supply your needs from this source so it pays to place an order well in advance of your scheduled planting time. See the Availabilty Notes with each variety to check on current availabilty and production waiting times.

More Information

  • Temperate and Subtropical Fruit Production, 2nd Edition - Edited by D.I.Jackson and N.E. Looney, CABI Publishing
  • IPM Services (2009) Ltd

Enquiry

Please email Andrew Boylan, andrew.boylan@edible.co.nz for quotes or for any other queries you may have regarding our products and services.

So that Andrew can respond to your enquiery promptly, please tell us:

  • Your address (so we have some idea of your climate)
  • The variety you are interested in
  • The approximate numbers required
  • Whether you a new grower or an established producer?

Many thanks





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