It is nowadays possible to use chemical substances to retard lawns growth and it is called chemical mowing. This research was carried out to investigate this issue at College of Agriculture, University of Kurdistan. The experiment was conducted as a completely randomized design with 4 treatments along with control and 4 replications. The seeds of Lolium perenne L. were first scarified by soaking them in 50 % sulfuric acid at half an hour and then after rinsing in water and finally the seeds were put in 20, 40, 60, and 80 mg.L-1 paclobutrazol solution and shacked for 24 h. In the control treatment seeds soaked in distillated water. The seeds were then sown in pots containing soil mixture. After seed emergence and several mowing, data recording was made. The results of this study indicated that with increasing in paclobutrazol concentration, clipping fresh and dry weight, verdure and root and also seed germination were reduced and visual quality was relatively increased. Thus, due to the adverse effects of high concentration the optimal concentration (20-40 mg.L-1 ) of paclobutrazol may be recommended used as a growth retardant in lawn management.
