Humic substances have been reported to increase soil water holding capacity and nutrient uptake of plants, however, little information is available on the specific effects of these compounds. In our study, we evaluated pure humic acid and commercial humic substance products for effects on moisture retention and phosphorus uptake of putting green turf. In a greenhouse study, creeping bentgrass was grown in tubs of calcareous sand simulating a USGA putting green and received organic acid treatments through a watering system at a standardized rate of 250 mg L-1 carbon. A water only control was also included. The soil was allowed to dry to 10% volumetric water content (VWC) before irrigation. In the field studies, the same humic acid, commercial product, and control treatments were applied to creeping bentgrass putting greens according to label rates. VWC was measured at weekly intervals and evaluated against a control for differences throughout two summers and tissue phosphorous was analyzed at the end of each summer. No visual differences were observed in either experiment along with no differences in tissue phosphorous, however, the humic acid did increase root length in the greenhouse study. In the greenhouse experiment, pure humic acid decreased water holding capacity of the soil and demonstrated hydrophobic properties. In the field, few differences in VWC were observed.