When should I harvest herbs?
Most herbs are ready to be harvested when flower buds appear on the plants, but before the buds open. The leaves contain the maximum amount of volatile oils at this stage of growth, giving the greatest flavor and fragrance to the finished product. Harvest herbs in the morning as soon as the dew evaporates from the foliage.
Leafy annual herbs can be cut back severely when harvested. Using a sharp knife or pruning shears, cut just above a leaf or pair of leaves. Leave approximately 4 to 6 inches of the stem for later growth. Do not cut back leafy perennial herbs as heavily as annual herbs. On perennials, remove the top one-third of growth.