To investigate the critical seeding date for Daeyeupdlkkae in the middle area of Korea, we seeded from 30 April to 20 July with 20-day intervals on the experimental field in Chungbuk-Do agricultural research and extension service. As seeding date was delayed, days to emergence were shortened, flowering and maturing date were delayed, but maturing period was not significantly affected by seeding date. Delayed seed date resulted in decreased stem length, culm diameter, number of branches per plant and number of nodes on the main stem. Cluster length and 1,000 grain weight increased but number of cluster per plant and number of seed capsules per cluster decreased with delayed seeding. Seeding date up to 10 June showed no effected on grain yield, but 30 June and 20 July decreased 10% and 38%, respectively.