How should I fertilize blackberries to ensure healthy growth and a bountiful harvest?

To fertilize blackberries for healthy growth and a bountiful harvest, apply a balanced fertilizer in early spring before new growth begins. Use a fertilizer with a ratio of 10-10-10 or similar, and follow the instructions on the package for application rates. Avoid over-fertilizing, as this can lead to excessive vegetative growth at the expense of fruit production. Additionally, consider conducting a soil test to determine specific nutrient needs for your blackberry plants.