ABSTRACT PLANT SPACINGS as affected by seed spacing and percent germination of the seed were investigated mathematically, by computer simulation, and by laboratory experiments. The geometric distribu-tion formula showed that for lots of seed with differ-ent germination percentages, the average number of plants per unit area could be kept constant by plant-ing more lower germinating seed. However, the plant-spacing distributions would differ. Results of lab-oratory experiments with grass seeds approximated the theoretical predictions; differences were not sig-nificant at the 5 percent level of confidence.