Studies to evaluate the effects of irrigation frequency and amount on the phenological development and lint yield of cotton (Gossypium hirsutum, (L.) var. Paymaster 145) were conducted in 1986, 1987, and 1988 in Halfway, TX. The five treatments were dryland and four levels of irrigation. Irrigation amounts of 0.4 and 1.0 times the estimated evapotranspiration were applied at 2 and 12 day intervals in 1986, and at 3 and 18 day intervals in 1987 and 1988. Irrigation water was applied with a Low Energy Precision Applicator (LEPA) linear system to alternate diked furrows. For each treatment, leaf, stem, and fruiting organ biomass, leaf area, root length density and water use were measured weekly throughout most of the growing season. Also, the number of fruiting structures as a function of plant node, fruiting branch, and time were monitored and mapped. Results for each year were different and can partially be explained due to weather variations and length of the growing season.