Annual bluegrass (Poa annua L.) is a common turfgrass species among finely mowed turfgrass. The plant exhibits diverse life cycles ranging from true annuals to long-lived perennials. These varieties are found coexisting with one another, but one variety may dominate. We conducted research to determine the influence of water as an ecological factor for the selection of certain varieties of annual bluegrass in finely mowed turfgrass. Three varieties of annual bluegrass were grown in a greenhouse using a sand and sphagnum peat moss root zone which met USGA (United States Golf Association) standards for golf course green conditions. Soil moisture conditions were monitored using a capacitance probes calibrated to the specific growth media. These probes measured the permittivity of the soil which directly correlated with the soil volumetric water content. Individual moisture sensors were placed in each of nine individual tubs which contained three of each variety of annual bluegrass. Hourly soil moisture measurements were recorded and plants were irrigated when the soil dried to volumetric water contents of 12%, 8%, and 4%. Plants were fertilized bi-weekly applying 24.41 kg N ha^-1, and mowed five days a week to 6mm in order to replicate golf course green conditions. Weekly area and inflorescence measurements were made on individual plants to monitor reproductive capability through tillering and flowering. Plant root and shoot dry mass was measured at the end of each trial to observe the effects on root:shoot ratios and above ground mass. Three replicates of this study were conducted over time.