Site Selection
Caneberries will grow best in full sun on soils that are deep and well drained. Sandy loam or loamy sand soils are optimum. Soils should be able to hold moisture well because berries require a constant supply of water. Optimum soil pH (acidity or alkalinity) is about 6.5, although plants will be productive at pHs between 6.0 and 7.5. You may lower the pH to some degree with applications of sulfur or raise it with applications of lime. Avoid planting in soils with a history of Verticillium wilt.
Blackberries are quite tolerant of a wide range of temperatures. Plants can be protected to some degree in colder climate regions by mulching. In warm summer areas, berry plants may be shorter lived and produce smaller and lower quality berries. Raspberries are much more susceptible to heat and cold. They are ideally suited to the areas of California where high summer temperatures are moderated by a coastal influence. However, acceptable crops of high-quality fruit may be harvested in other climate zones.
Planting
When planting caneberries, use only certified virus-free nursery stock rather than planting rooted cuttings taken from an existing, possibly virus-infected planting. Berries are generally planted from mid-January to March. If you use rooted cuttings from established plantings, make sure they are vigorous, disease-free plants.
Red raspberries should be spaced 2 to 3 feet apart in rows 8 to 10 feet apart. Blackberries should be spaced 4 to 6 feet apart, depending on how vigorous the cultivar is; more vigorous cultivars should be spaced further apart. Plants can be spaced along a fence or trellis. In areas where the soil dries quickly, such as in the Central Valley of California, caneberries are best planted on flat land. In the coastal areas of California where soils are easily waterlogged, plant on hills or raised beds.
After planting, canes can be cut back to 2 inches so new canes will begin growing from roots.
Watering
Berries require a lot of water but can be damaged by standing water on the soil surface, especially in early spring. Irrigation is usually required, with the frequency depending upon the soil texture and climate. Moisture is critical when fruit is ripening and also when flower buds form. Avoid overhead watering during the ripening stage because it may encourage fruit rot. When there is no rainfall, berries need about 1 inch of water per week. In warm climate areas, irrigate every 7 to 10 days in summer with light irrigations every 3 to 4 days during the harvest period. In coastal regions, only 3 to 4 irrigations may be required up to harvest. Continue to irrigate after the harvest to ensure the development of new canes.
Irrigation Tips
Overhead irrigation is not recommended because it promotes fruit rot and leaf rust and other disease problems. The best irrigation systems are minisprinklers or double drip lines that have numerous emitters which wet an entire band underneath the foliage. Keep the plants moist at all times without soaking and rotting the roots. A trickle hose may also work well.
Pruning
Semierect or erect blackberries: Other than removing any broken canes or roots, little pruning is done in the first year, though plants should be trellised as soon as the canes are long enough to reach the trellis wire. After the first year, pruning is done twice a year. The first pruning is in the winter. At this time, the lower side branches that are below the lower wire are removed. The laterals at the top of the trellis should be headed back to 12 to 15 inches. This will promote larger fruit by removing excess fruit wood. The next pruning is done just after the harvest. After harvest those canes that have born fruit are removed by cutting them down to the ground. During the spring and early summer though, replacement canes are growing out of the crown. These new canes are gently bundled off to the side, where they will continue to grow until the harvest is complete. After the harvest, the new canes that were growing from the base are trellised by wrapping them around the top wire and back down to the bottom wire in a fan shape.
Raspberries: On summer-bearing varieties, prune out spent fruiting canes any time after harvest. Keep 10 to 12 of the healthiest new canes and tie them to the top trellis. Late during the following winter, tie canes or wrap in a semicircle. This forces the lateral branches to grow in at a convenient height. In April, remove the first flush of new vigorous canes by cutting back when the growth is 7 to 10 inches high. New canes will develop shortly thereafter. This practice increases yield. For fall-bearing raspberries, remove the top half of the canes after fruiting, or remove the entire cane to the ground. If you leave half of the cane, you will get a summer crop the following June. If you remove the whole cane, you get only one crop in the fall, which is the preferred crop.
Trellising
Blackberries: Blackberries should be trellised as soon as the canes are long enough to reach the middle wire. Early trellising will increase fruit production. Trellis systems need to be sturdy in their construction. They should be at least 4.5 feet high with the first wire about 1.5 feet from the ground and the second wire 1 foot above the first. If rows are longer than 6 feet, support for the middle of the row will be necessary to support the wires firmly. New canes can sunburn easily if left on the ground too long. Put up only the larger canes, called primocanes, and prune out the smaller ones. Small canes only produce small fruit. If your plants are spaced 3 feet apart, leave up to nine good canes per plant. Place the long canes in a fan shape to spread out the canes. The canes should be 6 - 8 feet long. Put them over the top wire, wrap once around the middle wire and then remove the tip. Tipping or removing the ends of the canes forces out the laterals on which fruit will be borne the following season. A cane that is not tipped will continue to grow. The farther the berries are from the crown of the plant, the smaller they will be.
Raspberries: For raspberries (see diagram), during mid- to late summer, tie new vigorous canes to the top wire, leaving the lower two wires on the ground. Let the canes grow through fall and winter. During the following May, reattach the lower training wire and gather up the canes inside the training wire. By August, new canes will be growing up though the center of the fruiting canes. Remove the canes that have fruited and again tie up the new canes onto the top wire.
Fertilizing
Blackberries and raspberries require about 1.25 pounds of ammonium sulfate per year, per plant or 0.25 pound of actual nitrogen per year, per plant. Apply fertilizer just prior to an irrigation by banding the fertilizer out 12 inches from the plant. Apply all the fertilizer in the winter or in smaller increments during the growing season, with one application in spring, two applications in midsummer and one more in fall.
In some climate zones, potassium and phosphorous may be limited and may need to be added to the soil. Soils will need to be tested.
Fertilizing Tips
If you use manure, compost, or another source of organic fertilizer, apply it in the late fall or early winter.
Inorganic fertilizers out of a bag should be spread over the surface of the soil in the row in early spring just when growth is starting. If plants lack vigor, apply additional fertilizer at bloom.
Harvesting and Storing
Berries develop their best flavor when they begin to turn their normal ripe color—red or black, yellow or purple—depending upon the variety. Fruit usually ripens over a 2- to 3-week period in May or June or may extend into fall for the late-ripening varieties. Berries have a short shelf life and should be processed within a day or two after harvest. Berries can be frozen, canned, or made into jams and jellies or pies and other desserts.
Sanitation
Old canes can be shredded and disced into the garden row or placed into the compost pile. Dispose of plants infected with crown gall, Verticillium wilt, or virus.
