The naturally occurring or derived plant growth regulators indoleacetic acid, gibberellic acid, kinetin, and kinetin riboside were evaluated for their effects on yield, agronomic traits, and allelochemicals of cotton Gossypium hirsutum over a several year period. The compounds were applied as foliar sprays at two levels to fruiting cotton at two week intervals. Terminal leaves and squares were harvested for analysis of allelochemicals one week after each spray. The plots were machine harvested one time for yield determination on about September 30. No multiyear trends were evident for yields with any of the plant growth hormones. Kinetin and gibberellic acid appeared to increase bud gossypol in some years.