Recently harvested true seed of potato frequently requires several months for complete germination. Gibberellic acid (GA 3 ) has a pronounced effect on seed germination, but this effect is influenced by temperature. As the temperature approaches 80 F, germination decreases considerably irrespective of GA 3 treatment. Potato seed germination is also favored by low temperature, but constant low temperature alone does not insure complete germination of dormant seeds. More than 95% germination of dormant seeds can be obtained within a week either by application of GA 3 at low temperature or by diurnal alternation of temperature. A possible mechanism for control of seed germination is discussed.