The first step in the collection of medicinal plants is to acquaint oneself with the market demands. Dealers in crude botanical drugs usually publish lists of the plants they handle and indicate the general range of prices. With such information at hand, and with the aid of this publication, the prospective collector should be able to determine which plants found in his locality offer the best opportunity for profit.
It frequently happens that after gathering considerable quantities of some plant the collector finds that the market is fully supplied at the time and either there is no sale for it or it can be sold only at a price that will not compensate him for his labor. Such a situation may usually be avoided by first submitting representative samples of the material to be collected, together with a statement of the approximate quantity that can be furnished, to a number of reliable dealers This will generally bring information concerning the market possibilities and the returns that may be expected. Such procedure is especially recommended in the case of plants that are liable to deteriorate in a relatively short time, making it inadvisable to hold them until market conditions improve. Some of the dealers in crude drugs are willing to cooperate in this way with collectors, in order to prevent loss through overcollection and to encourage the collection of adequate supplies of the most-needed plants.
The medicinal value of botanical drugs depends to a large extent on the time of their collection. Roots from annual plants should generally be dug just before the flowering period; those of biennial and perennial plants should be gathered late in the fall or early in the spring, because during the growing season they are deficient in their active constituents and are of poorer quality generally. Barks also should preferably be collected during the dormant season when the sap is not flowing. Leaves and herbs are of most value when collected during the flowering period or just before they have finished growing. Flowers should always be gathered when they first open. Wherever definite information on these points has been available it has been included in the discussion of the various plants.
The proper preparation of the collected material is of the utmost importance. If the material contains dirt or other foreign matter, or if it is moldy or has an undesirable color or odor, it may be rejected by the dealers or purchased only at a reduced price. [loots should be thoroughly freed from adhering soil and other dirt. Fibrous roots, or rootstocks with numerous small roots or rootless, require careful washing to remove such foreign matter. The larger stems of herbs and leaves should be discarded, as they possess little or no value, and leaves that are partly dried from age or that are discolored or injured by disease or insects should be excluded if the best price is to be obtained.
The material must be carefully dried. All plant material, in whatever form, is easily spoiled in both appearance and value if improper methods are used to remove the large quantity of moisture that is usually present. Fleshy roots dry very slowly and frequently become moldy unless they are sliced across or lengthwise to permit more rapid evaporation of the moisture. In the drug market such roots occur m various forms, and information on this point should be secured from the dealers or from experienced collectors so that the dried material may conform to market requirements. Leaves readily lose their green color while drying and sometimes become brown or even black. They should, therefore, be spread out in a well-ventilated room, especially in cloudy weather, and dried as rapidly as possible. Exposure to direct bright sunlight is undesirable because it frequently causes bleaching of the leaves. Fruits, particularly those that are juicy, are especially difficult to handle on account of their tendency to become sour or moldy. They should preferably be spread out in thin layers on wire or cloth screens that will permit a thorough circulation of air end on which they can be frequently stirred. Seeds must be thoroughly cured; even ripe seeds that appear to be dry will frequently heat and spoil if stored without having been spread out and allowed to dry for at least several days.
The best way to store the dried material is to pack it in clean bags or boxes. If, however, the material is likely to be injured by exposure to air or light, or if it is subject to the attack of insects, it should be placed in tightly closed cans or other receptacles and marketed at the earliest opportunity.
Note: More detailed information on the drying of crude drugs, including also directions for constructing drying rooms and sheds, is contained in Farmers' Bulletin No. 1231 Drying Crude Drugs.