The leaves of most herbs should be harvested for drying before the flowers open, when the plants are in bud. Gather on a dry day—early in the morning, once the dew has dried, but before the day’s heat starts evaporating the essential oils. If the leaves are dirty, or have soil splashed on them, swish the stems briefly in cold water, roll in a towel, and pat dry.
Large-leaved herbs, such as mint, basil, or marjoram, can be dried in two ways. Individual leaves can be picked off—discarding any that are damaged—and spread on wire racks or sheets of paper towel to dry in a warm dark place. They should be turned frequently for the first two days to dry them rapidly and retain the flavor. Alternatively, they can be tied in small bunches and hung to dry on coat hangers, or in brown paper bags, in an airy place.
Small-leaved herbs, such as rosemary, tarragon, or thyme, can also be hung in bunches in the open, but dry better if placed in brown paper bags. Leave the tops open for the first few days to let most of the moisture escape, then tie loosely closed to keep the herbs clean.
Do not put different herbs in the same bag, or close together in bunches. Strong-flavored herbs may overpower more delicate ones.