How to Grow Blackberries in Polk County, Florida

Till the soil to a depth of about 1 foot in a well-drained area with good air circulation and abundant sunlight. Hilltops and hill slopes are ideal. Avoid low-lying areas. Homeowners who are limited in their site selection can build up a small hill or bed to promote drainage and air flow. Blackberries can grow in most soil conditions, but deep, well-drained areas are ideal.

Treat the planting strips (about 3 feet wide) with an herbicide to remove all weeds and vegetation. The University of Florida Cooperative Extension Program recommends a treatment containing glyphosate--the main ingredient in such brand names as Roundup and Terminix.

Plant your blackberry plants December through February in Florida. Space the rows about 8 to 10 feet apart and the plants 2 to 5 feet apart in each row, depending on the species or cultivar. Give trailing blackberries more room in each row. Cut the plant shoots to about 6 inches and plant them in the ground deep enough to accommodate the roots (use the depth that the plants were at when they came from the nursery as a guide). Spread the roots, but be careful not to damage or bend them. Cover the roots with 2 to 4 inches of soil.

Apply a fertilizer (10-10-10 N-P-K) in the late spring or summer. Do not fertilize at planting time. Apply in an 18-inch circle around individual plants or along rows 12 to 18 inches from the plants. Blackberries don’t require much fertilizer; their roots are shallow and can burn.

Use a fairly thick mulch of bark, straw and mushroom mulch to a depth of about 1 to 2 inches in an area at least a foot around each plant.

Irrigate well, especially the first year. Drip irrigation is preferred; the key is to avoid getting the foliage wet as much as possible to avoid disease.

Remove weeds by hand. Avoid pesticides during the first year of cultivation.