Changes in the federal farm program, in rainfall pattern and quantity, and increased incidence of herbicide resistant weeds and diseases have generated increased interest in spring grains in the Pacific Northwest. However, spring grains have traditionally been treated as minor crops in this region, thus little research has been done on them. Complicating the situation is the diversity in spring growing conditions as well as crops grown. This study was conducted to a) assess the impact of seeding date on the growth and development of the spring grains and b) to determine the differences or extent of differences among genetically diverse grains. Planting date and cultivar had significant effects on number of leaves and tillers as well as dry matter production. The differences among planting dates were mainly as a result of variations in temperature, though soil moisture was of significance in some cases. Among the cultivars, Alpowa had a high tillering rate, while Westbred936 was poor. The leaves of the cultivars generally emerged at a constant rate (with a few exceptions) within a given planting date, but rates differed among planting dates. Though significant differences in rate of leaf emergence were observed among cultivars, rate of leaf emergence in wheat as a group was not significantly different from that of the barley or oat cultivar evaluated. Phyllochron decreased with later sowing in only the first year. In the second year, no consistent increase or decrease in phyllochron with planting date was observed. Rate of dry matter production followed an inverse quadratic polynomial trend. Rate increased slowly during early growth and later rising sharply as plant matured regardless of planting date. Among the cultivars, barley plants showed clear superiority in dry matter accumulation. This is likely the reason why barleys seemed to show superior growth to all the other cultivars. A relationship between vegetative growth and grain yields was observed; however, assimilate redistribution was also found to play significant role. Results obtained were a clear reflection of differences in environmental conditions for each year. / Graduation date: 2000