What to Use to Speed the Growth of My Blackberries

Site Location

• Plant blackberries in a sunny location. Although wild blackberries grow in woodland areas, cultivated berries produce more fruit in full sun. Dry, cold winds can chill blackberries and dry out canes. A sunny gentle slope protected from winds by buildings or trees is ideal. Add 2 to 3 inches of compost or rotted manure to the soil and dig it in to a depth of 8 inches. Blackberries prefer a soil pH between 5.5 and 7.0. If the pH is higher or lower than this range, adjust it by adding lime or sulfur. Blackberries tolerate clay, loam or sand soil, but it must be well drained. Build raised beds if the soil remains soggy.

Fertilizer

• Send a soil sample to a university extension office if you are unsure of your soil's fertility. If plants seem to grow well, your soil is probably reasonably fertile. Unless you suspect a nutrient deficiency, side dress blackberry plants in the spring with a shovelful of manure or 1/2 cup of 10-10-10 fertilizer per foot of row. The extra nutrition gets the blackberries off to a good start each season.

Watering

• All bramble fruits need ample water to produce good yields. Water to keep the soil evenly moist at all times. In dry areas, water as much as every other day. Providing blackberries with enough water is the most critical component of encouraging fast growth. Use drip hoses, flooding or soaker hoses instead of overhead sprinklers to keep the leaves dry. Lay untreated grass clippings, straw or wood chips on the soil as a mulch to conserve moisture and keep weeds down.

Pruning and Trellising

• Adequate pruning keeps blackberries vigorous and disease-free. Prune new plants back to 3 feet midsummer to encourage lateral growth, which will produce fruit. The following winter, cut each lateral branch back to half its length. Cut canes that have produced fruit back to ground level in the fall after harvest. Thin the remaining new canes so they stand about 6 inches apart. Trellis semierect or trailing blackberries. Erect blackberries don't generally need support.