Light and frequent (LF) and deep and infrequent (DI) irrigation are two common practices for golf course managers. Few studies have compared the effects of these two opposing irrigation practices on summer root performance in creeping bentgrass (Agrostis stolonifera L.). The objectives of this field study were to quantify summer root development and longevity in response to LF vs. DI irrigation in 'Providence' creeping bentgrass grown on a sand-based rootzone. The LF plots were irrigated daily to moisten the upper 4 to 6 cm of soil, whereas DI plots were irrigated at leaf wilt to wet soil to a depth >= 24 cm. Root measurements were obtained using the minirhizotron imaging technique and included total root count, total root length (TRL), total root surface area (TRSA), and average root diameter. When averaged over the entire 0- to 24-cm rootzone depth, DI-irrigated creeping bentgrass produced a greater number of roots, longer root lengths, and a larger root surface area than LF-irrigated turf. Average root diameters were smaller in DI-irrigated creeping bentgrass in the summer of 2007. Compared with data collected in 2006, the 2-yr-old turf had 55 and 32% fewer roots in LF- and DI-irrigated bentgrass by September 2007, respectively. There were similar reductions in TRL and TRSA between years in both irrigation regimes. Deep and infrequent irrigation stimulated root growth throughout the 0- to 24-cm rootzone in May and June and promoted root longevity in summer.