Pre-treatment: For dryland seedings with less than 16 inches mean annual precipitation, fall dormant seedings are preferred. Dryland plantings in areas receiving 18 or more inches of annual precipitation should be sown in the spring. In areas receiving 16-18 inches of precipitation, either spring or fall seedings can be made. Irrigated seedings may be made at any time. No pretreatment required for container propagation.

Establishment: Seed ripens in mid to late July in the Pullman area. It is collected when the inflorescence begins to dry and the seed is in the soft to hard dough stage but before it shatters from the inflorescence. Seed can be stripped from the inflorescence or the inflorescence can be clipped from the plant. Harvested seed is stored in paper bags at room temperature until cleaned.

Source: npn.rngr.net