GROWING BLACKBERRIES Quick Links Before You Start Planting Planting Year Irrigation Fertilization Tissue Culture Bramble Plants Pruning Quick Reference BEFORE YOU START Avoid planting blackberries in soils where previous crops have included strawberries, raspberries, potatoes, tomatoes, eggplants, or peppers. These crops may harbor soil pathogens, which will affect the health and performance of your new plants. PLANTING If the soil is not well-drained, raise the soil height of the planting rows or build twelve to eighteen inches (12–18") wide raised beds. Plant as soon as possible in the spring, after your soil has warmed to 50°F. Planting too early, in cool, damp soil can delay development or cause roots to rot. Do not fertilize at planting. Planting at the correct depth is important. Your planting rows should be measured and maintained at no more than a twelve to eighteen inches (12–18") width. When planting dormant, bare-root plants, use a hoe to make a two-inch (2") deep trench the length of the bed. Lay the roots horizontally along the trench, two inches (2") deep. You may need to position some canes deeper than two inches (2") so that all roots on the cane are covered, still laying the length of the roots parallel to the soil surface at the two-inch depth. Cover them immediately. The fine root system should not be allowed to dry out during the planting process, which can happen very quickly on a warm day. CAUTION: If set too deeply, they will not easily send up new canes from the root as they must. Plant tissue culture plugs one-half to one inch (½–1") deeper than the soil level of the plant. PLANTING YEAR New growth may not appear for five to six (5–6) weeks. The cane portion of the plant may never lead out; expect most, if not all new growth to come from the roots. If you want to check for root development after six to seven (6–7) weeks, dig very gently two to three inches (2–3") away from the cane. Be careful not to damage delicate new sprouts that have not yet broken the soil surface. If the plants are not leafing out or sprouting new growth from the roots after seven to eight (7–8) weeks, call us. IRRIGATION Water thoroughly after planting and maintain good soil moisture until plants are well established. The plants should then receive one to two inches (1–2")of rainfall or the equivalent each week throughout the season. Do not water every day – one to three (1–3)times per week is sufficient. FERTILIZATION You may thoroughly incorporate a light amount of fertilizer at least two (2) weeks prior to planting. Do not fertilize when planting, wait until new transplants are well established. For optimum growth and production, home gardeners should apply one-half to three-quarters pound (½ lb. – ¾ lb.) of 10-10-10 fertilizer per 100 sq. ft. each spring and an additional 1 lb. of 10-10-10 fertilizer per 100 sq. ft. in mid-summer. Do not fertilize after July 1, as late fertilization generates tender new growth which will be more susceptible to winter injury. Commercial growers should use 500 pounds (lbs.) of 10-10-10 per acre or make applications according to soil tests. Additional applications may be necessary according to weather and/or leaching conditions. TISSUE CULTURE BRAMBLE PLANTS PLANTING Cover the soil plug with one-half to one inch (½”-1”) of soil, using the same spacing as bare root plants. Fertilize TC plug plants the same as bare-rooted plants using one-half to three-quarters pound (½ lb. – ¾ lb.) of 10-10-10 per 100 sq. ft. incorporated at least two to three (2-3) weeks prior to planting or wait until plants are well established and then side-dress with 10-10-10 to maintain vigorous growth. Irrigate well after planting. Maintain good moisture levels until the plants are well established or for four to six (4–6) weeks. Use care when applying herbicide on TC plants. We have had good results using four pounds (4 lbs.) per acre of Devrinol 50W. In our experience, other herbicides will damage these plants. PRUNING Primocane-Bearing (Fall-Bearing/Everbearing) Double Cropping Summer Tipping Primocanes require pruning during the growing season, called tipping. Tipping makes plant management easier and increases yield potential. When primocanes reach fifteen inches (12–15") in height, tip the top one inch (1") of the primocanes to encourage the cane to grow lower lateral branches. This process increases the places where the plant can produce fruit. As the lateral branches reach thirty inches (30"), tip the top one inch (1") of the tips. Tips are tender and can be removed by pinching between your thumbnail and finger or with pruning shears. This process stimulates earlier fruit development, increases yield, and maintains a proper plant height for easier management and harvest. Winter Pruning In late winter, remove the spent floricanes from the previous year. These dead canes are tan or white. Cut at the base of the cane, as close to the ground as possible. Do not cut the reddish maroon canes, as these are the previous year's primocanes that have overwintered and become floricanes. Remove any portions from the cane that have fruited the previous year. This cane portion is now dead and will not produce any fruit. Cut below where the dead portion ends. Cut lateral branches back to a manageable length of twelve to eighteen inches (12–18"). Trim back any dead portions that remain. Primocane-Bearing (Fall-Bearing/Everbearing) Single Crop Cut all canes at the base as close to the ground as possible in late winter, before the emergence of buds. Ensure that all cut canes are removed from the area to lessen disease pressure. This process allows the plant to focus all its energy on producing new primocanes in the spring. Primocanes will produce fruit in late summer and fall, depending on the location. Floricane-Bearing (Summer-Bearing) Blackberries Primocanes require pruning during the growing season, called tipping. Tipping makes plant management easier and increases yield potential. In midsummer (typically late June and July), when first-year canes reach five to six feet (5–6') in height or six inches (6") over the top wire of the trellis, tip the first-year canes to four feet (4'). Tipping stops terminal growth and establishes fruiting laterals. Thin the remaining primocanes to six to eight (6–8) canes per three feet (3') in a row or per hill. Do not prune floricanes before the fruiting season unless diseased or damaged. When the fruiting season ends, cut out spent fruiting canes at the base, as close to the ground as possible. Removing spent floricanes provides more space for new primocanes to grow the following year. Do not cut the primocanes; primocanes overwinter and develop fruit the following season. In late fall, cut laterals back to six to eight inches (6–8"). If using the staked management system, prune canes to the height of the stake and follow the above pruning instructions. BLACKBERRY PLANT QUICK REFERENCE Spacing Blackberries should be planted three to four feet (3–5') apart. Recommend eight to twelve feet (8–12') between rows depending on the machinery. Irrigation Soak in water using Agri-gel™ for one to two (1–2) hours before planting (except tissue culture plugs). Water thoroughly after planting. One to two inches (1–2") of rainfall or equivalent per week. Fertilization Before planting add one-half to three-quarters pound (½ – ¾ lb.) of 10–10–10 per 100 square feet. Commercial growers should use 500 pounds per acre. An additional one pound of 10–10–10 per 100 square feet can be applied in July or August and in early spring in the following years. pH: 6.5–6.8. Weed Control Regular cultivation is necessary during the growing season. Roots are shallow—don’t cultivate more than an inch deep. Mulching during establishments can help control weeds. Contact a local extension for chemical recommendations. Trellis We suggest plants are supported by a four (4)-wire trellis or put into a staked–hill system.
