Field studies were conducted to evaluate the effect of the plant growth regulator, Pentia, on lint yield and fiber quality under various application rates and timing schemes. Treatments were applied to cotton var. ‘DP 555 BG/RR'. Comparisons for treatments initiated at pinhead square and early bloom are reported. Pentia rates ranged from 8 to 16 oz product per acre for each application. The use of Pentia in combination with a nonionic surfactant and ammonium sulfate were also evaluated.