Inspect the bush for ripe berries. Mature blackberries have a deep, even color, dull skin and feel soft and juicy.
Grasp the berry gently between your thumb and forefinger. Lift the berry up toward the stem. Fully ripe berry berries separate easily without pulling or tugging.
Place the berry inside a shallow box. Stack the harvested berries no more than two layers deep in the collection box, or the berries on top crush those on the bottom.
Leave unripened berries on the bush to ripen further. Pick the berries daily throughout the two to four week harvest season so the blackberries are only harvested at their peak ripeness.