Broom rape is a small weed 6 to 15 inches high that is parasitic on the roots of hemp, tobacco, and tomatoes, it usually grows in clumps and has purple flowers, which produce many very small seeds. These adhere to the waxy flower parts surrounding the hempseed and are distributed in this manner. Broom rape can be very serious on hemp if proper control measures are not followed. Only well-cleaned hempseed and seed from fields containing no broom rape should be sown. Hemp has been recommended as a weed-control crop. Its dense, tall growth helps to kill out many common weeds. The noxious bindweed, a member of the morning-glory family, is checked to some extent by hemp. Unfortunately, bindweed and several other species of morning-glory have seeds so near the same size and weight of hempseed that mixtures obtained in producing hempseed are carried to the field planted for fiber production. In growing hemp for seed all vine weeds of this type found on the hemp stalks should be removed before the hemp plants begin to produce seed. [Illustration] _Harvesting_ =Time to Harvest= Hemp is harvested for seed production when the plant on being shaken sheds most of its seed. This occurs when the seeds are fully mature on the middle branches. The seeds will mature on the lower branches first and on the top of the plant last. The common method of harvesting hemp for seed production is to cut it by hand and shock it to permit more seed to mature and cure before threshing. The harvesting should be in the early morning or on damp days when the seeds do not shatter so much as they do in the warmer and drier part of the day. Threshing of the seed hemp should be done on dry afternoons. In threshing, the seed shocks should be placed on large canvas cloths 24 by 24 feet and then be beaten with long sticks to remove the seed. Hemp is harvested for fiber production when the male plants are in full flower and are shedding pollen. By harvesting before the male plants die, the retting of both male and female plants is more uniform, as both types of plants are still green and growing. The harvesting period may extend for 2 weeks or longer. Very early harvested hemp may produce a finer and softer fiber than that harvested later, but it is usually weaker. The fiber from hemp that has been harvested so late that many seeds have matured does not possess so good cordage and textile characteristics as fiber from hemp harvested earlier. Hemp stalks should be relatively free of leaves except a few at the very top before harvesting. This is important when hemp is shocked after harvest, as it makes the top of the shock smaller so that less rain can enter the shock. [Illustration] =Machinery=