Holes are dug 25 to 30 feet apart in the center of each row; they are 3 feet deep and slightly wider than the diameter of the bases of the posts. Immediately after the holes are dug, a 3-foot section of plastic pipe is set into each hole to maintain integrity. Near the time of harvest, the T-posts are inserted into the plastic-lined holes. After harvest, the twine is cut and the posts are removed and stored for another year. Because the plastic pipes are buried, they do not interfere with cane-cutting operations. Trellising of floricane fruiting raspberry and blackberry plants helps reduce primocane interference and improves production. Without trellising, fruiting canes must be cut short in the dormant season to prevent canes from breaking or tipping over. Because most of the fruit buds are on the top half of the cane, topping low can significantly reduce the productivity of a planting. Staking brambles in a hill is a trellis system that is occasionally used. Advantages are low cost, ease of harvest and suitability for two-way cultivation. The disadvantage is low yields per unit area. Trellising to a single wire 3 or 4 feet above the ground prevents cane breakage but allows only a small amount of light to reach the lower portions of canes and forces primocane growth toward the aisles; this growth can interfere significantly with spraying and harvesting.
Blackberries respond well to soils with organic matter added before planting. Livestock manure can be soil-incorporated in the fall at a rate of 10-15 tons per acre (2-3 bushels per 100 square feet). Chicken manure can be applied in the fall at rates of 2-3 tons per acre. Large amounts of organic matter can be added the year before planting by incorporating green manure crops like Sudan grass in the fall, or winter wheat, barley, rye, or oats in the spring. Soils should be plowed about 9 inches deep, disked, and harrowed before planting. Fields should be irrigated before planting to insure good soil moisture. Blackberry planting sites should be totally free of perennial weeds like bindweed. Bindweed seed can remain dormant in the soil for 20 to 30 years and is very difficult to control. Other perennial weeds like Bermuda grass and Johnsongrass should be controlled the year before planting. Trailing blackberries, particularly western trailing blackberries, develop deep root systems capable of getting moisture from considerable depths, making them more drought resistant than most erect blackberries or raspberries. They are also capable of producing greater yields than erect blackberries. Erect blackberries, however, tend to be more cold hardy. Trailing blackberries tend to flower and ripen earlier than erect cultivars, which makes them more susceptible to late frosts. Trailing blackberries tend to produce smaller, more open fruit clusters that are sweeter but tend to bruise more easily than those of erect cultivars. Most blackberry cultivars are self-pollinated, but yields and quality tend to improve with cross-pollination. At least two or more colonies of bees per acre are recommended. This allowed bees and other insects to cross-pollinate the plants. Thus, man actually started a vast blackberry-breeding project. For the last 150 years, man has been cashing in on this project by selecting the best of the wild hybrids and trying them under cultivation.