Consul-General Richard Guenther, of Frankfort quotes from the exhaustive report of Richard Gomolla in the "Tropenpflanzer" the following summary as to the cultivation and preparation of vanilla in German East Africa:
The best variety of vanilla comes from vanilla plani-folia, which requires a mucky, porous soil. The plant thrives up to a height of about 1600 feet above sea level and as its fleshy roots do not penetrate deep into the soil it requires only a proportionately thin layer of soil. The plant bears merchantable fruit in the third year, sometimes even in the second year, which require from seven to eight months to mature, and the harvest takes place from April to June. Five to seven harvests are made from the same plant before it is exhausted. New plants must not be planted in the same place as the old.
Protection against wind, also shade, is of great importance for the growth of the plant, and therefore the fields must be surrounded by trees and hedges. Grubs and snails are enemies of the vanilla plant; the former eat the roots, the latter the young sprouts and beans. While in the third year only about one-tenth part of the plants blossom, the percentage increases from year to year up to the seventh. The cultivation of vanilla in German East Africa is impeded by the absence of insects which are instrumental in fructifying the vanilla blossoms. Each separate flower has therefore to be fructified by human hands, the cover of the stigma being raised by means of a thin little rod and the pillen, which is just above the cover, is pressed against the stigma.
When the young beans have grown to the length of a finger, they must be closely inspected and all defective ones must be cut off. The beans mature from seven to eight months after the fructification process. The ripe beans have a yellowish green color.
The way of preparing the beans varies, but an ever-inci'easing temperature is required to dry them and obtain the well-known brown-black color. In this way, the thin-skinned bean with its fine aroma is produced. If hot water is used for heating the beans, they are placed in baskets and immersed in it. The water has a temperature of 80° to 84° R. Afterwards the beans are packed into wooden boxes, which are lined with woolen cloth, and closed. The next day they must have a glassy appearance. They are then again wrapped in dark woolen covers and laid in the sun to dry. If the weather is rainy, they must be dried in a dry-room at a temperature of 50° R, but an after drying in an airy room of from two to four weeks is necessary. After that the dry beans are packed in tin boxes, where they, however, require close inspection, and have to be repacked every week in order to remove diseased beans or such which have become moldy.
The value of the beans is measured by their length, which is from 12 to 25 centimeters. For shipment they are sorted, bound in bundles, and put into tight but not soldered tin boxes, which are now lined with paper instead of tinfoil, as formerly. Black mould is especially dangerous to the beans, while white mould is rather harmless.