Older generations of herbalists attached great importance to the time of collection. The most auspicious hour may vary from herb to herb and is recorded in the old herbals. The kind of weather, with presence or absence of sunlight, are now known to affect the potency of a plant. Much herb lore of history has been vindicated by today’s scientific research, with the discovery that the quality of active ingredients depends upon such variables as season, location, and the time of day when gathered. Different parts of herbs are gathered at different times.

Herbs should be collected in dry weather after the dew has lifted. Where not possible to cull by hand, a sharp knife or scythe should be used. In general, aerial parts should be gathered before flowering. Rhizomes and roots are gathered in the autumn when the leaves decline for maximum therapeutic action. Wash and clean roots, and ensure they do not touch when drying. Flowers are picked just before breaking into full bloom. Barks and twigs are collected in the spring when the sap is rising.

Spread out fresh material to dry in a thin layer, without delay. Use trays, wire racks, even lengths of string netting. Packed into bundles without circulation of air encourages bruising, fermentation and mould that destroy medicinal properties.

Almost any shed can be adapted as a drying shed, provided there is adequate ventilation. Artificial heat may be required for complete drying. Leaves should not be dried to the point where they powder when rubbed between the palms. Most herbs and roots lose about four-fifths of their weight on drying. When the hand is plunged into a bag of well-dried herbs they should feel warm and crisp to the touch. Roots are dried to the point of brittleness, breaking easily.

Present-day growers achieve high standards of drying. Since passage of the Medicine’s Act, 1968, the quality of herbs on sale has been good. Dried herbs should be stored away from direct sunlight, or they will lose their colour and efficacy.