Basil branches should be pruned when they have six or more leaves. For best growth, they should be pruned down to the first set of leaves. The leaves should also be picked well below the flower buds to encourage bushy growth, ideally before the flower buds open. Basil needs to be pruned continually to encourage its growth.
When the plant is about 6 inches tall, leaves from the stem tips should be removed to keep the plant from bolting. Although flowers can be snipped off if they appear, they are edible and shouldn't be discarded. Flowers that are left on the plant can cause the leaves to have a bitter taste.
Basil should be pruned or cut in the mornings after the dew has dried. The leaves shouldn't be washed, because this washes away their aromatic oils.
Basil is easy to grow and to transplant. As an annual, it thrives in hot weather and is vulnerable to frosts. If the gardener senses that a freeze is coming, he should harvest all the basil in the garden before the cold weather kills the plants.
The leaves of basil can be used fresh, dried, or placed in oil or vinegar and refrigerated.