For basic understanding on pasture irrigation, this experiment was carried out to determine the effects of spring drought in relation to growing stage on the growth, dry matter yield and quality of grasses. Duration of non-irrigated treatments were early vegetative stage (Mar. 24-Apr. 5, T₁), vegetative stage (Apr. 6-Apr. 18, T₂), boot stage (Apr. 19-May 1, T₃), and heading stage (May 2-May 14, T₄) and irrigated plot (control, T_5) was involved. During experimental period, rainfall was controlled artificially, irrigation point was 0.5-1.0 bar, and the experiment was conducted at LES in Suwon, 1988. 1. With irrigation, temperature of sod surface and underground was decreased. The highest decreasing effect was observed in T₄, and then T₃, T₂, and T₁, in that order. 2. In grass growth and yield, boot stage (T₃) was the most harmful (DM 3.57 MT ha^-1 ), and there were not significant differences among T₁, T₂, T₄ and T_5. However, regrowth yield was not significantly different among all treatments. 3. DM production per mm of water applied was also the lowest in boot stage (42.0 ㎏), and then in T_5 (46.3 ㎏). That of heading stage (57.4 ㎏ ha^-1 ) was the highest (P $lt;0.05). 4. DM digestibility and nitrate nitrogen concentration of grasses in T_5 were slightly lower than in T₁, T₂, T₃ and T₄, but the differences were not significantly different when compared with T_5. 5. The results indicates that enough water applied during boot stage may be desirable to improve pasture irrigation efficiency, and spring drought stress of short interval on regrowth yield and quality of grasses was very little.