In many parts of the crimson clover region it is not necessary to inoculate the seed; but if clover has not been successfully grown on a soil, inoculation of the seed is good insurance. If the plants are not inoculated they will develop slowly, become yellow, and die. Inoculated plants are able to obtain about two-thirds of their nitrogen from the air through their root nodules. The plants may be artificially inoculated by applying pure cultures of the bacteria to the seed or by scattering soil from a field where inoculated crimson clover has been grown. Two hundred to three hundred pounds per acre of such soil evenly distributed at seeding time is sufficient.