Examine the cluster of blueberries. The blueberries will be ripe when they are completely blue in color, from the stem end to the calyx end. The calyx is the outer cap of the blueberry opposite the stem. If the blueberries have green or red near the stem end, do not pick them yet.
Press the blueberries between your fingers -- ripe blueberries feel firm to the touch, rather than soft or mushy.
Taste your blueberries for ripeness. Ripe blueberries taste sweet; unripe blueberries will not have much flavor or sweetness.
Harvest your blueberry bushes in the months of June through August, since blueberries ripen during this time. You will need to harvest the same bushes repeatedly since blueberries ripen in bursts.