Yield of irrigated castorbeans (Ricinus communis L.) in Nebraska was highest when planted the first 2 weeks of May, particularly when Alternaria leaf spot [Alternaria ricini (Yoshii) Hansford] was not a factor in the results. for nonirrigated castorbeans there was little difference in yield for any May plantings. April and June plantings were lower in yield. The time required for emergence was correlated with soil temperature and decreased with later plantings. Total emergence increased from 55% for March planting to 75% for June plantings. Lodging was inversely correlated with hypocotyl diameter within but not between varieties. Weight per 100 seeds in most cases was highest for primary racemes and progressively lower for secondary, tertiary, and quaternary racemes. Seed from racemes, particularly tertiary and quaternary, rapidly decreased in weight with later plantings. A positive and significant correlation coefficient of 0.88 was found between weight per 100 seeds and germination percentage. Seeds from earlier planting dates tend to have higher germination.