In recent years, many Louisiana producers have planted Maturity Group IV soybeans earlier than the optimal window indicated by previous research. Two studies were initiated in 2005, in a narrow and a wide row spacing, to compare Maturity Group III and IV variety responses to a wide range of planting dates. In 2006, the two row spacings were combined into one study so that their interaction with planting date could be observed. The experimental design was a split split plot, with planting dates as whole plots, row spacings as split plots, and varieties as split split plots. Planting dates ranged from March 15 to early June. Data will be reported from 2006, and will include stand establishment, timing of growth stages, plant height, and yield.