In 1987, field studies were conducted to evaluate possible interactions between row spacing and a range of water supplies at two locations, on a sandy soil and on a clay soil. Under irrigated conditions, 0.33 and 0.67 meter spacings had greater early fruit development and yield than the 1.0 meter spacing, due to increased leaf area development and light interception. The cotton simulation model GOSSYM underpredicted yield and growth parameters, but generally predicted development well.