The sand used for USGA green construction in Scandinavia is usually amended with peat or compost, but there is no requirement for organic amendment (OA) of USGA green rootzones. Especially in areas where the annual precipitation exceeds 1000 mm, it has been argued that greens should be constructed of straight sand as OA is supposed to reduce drainage, air-filled porosity, root development and turf quality over time. Thus, the objective of this experiment was to compare USGA greens constructed without OA with greens constructed with peat or compost amendments of the rootzone. Results from the grow-in year have earlier been presented by Aamlid (2005).