Optimal Nitrogen and Potassium Fertilization Rates for Establishment of Warm‐Season Putting Greens

Proper fertilization of golf course putting greens during grow‐in provides rapid turfgrass cover, high quality putting surfaces, and limits environmental impacts. Different levels of N and K were applied to ‘TifDwarf’ and ‘TifEagle’ bermudagrasses [ Cynodon dactylon (L.) Pers. × C. transvaalensis Burt Davy], ‘SeaDwarf’ seashore paspalum ( Paspalum vaginatum Swartz), and ‘PristineFlora’ zoysiagrass [ Zoysia japonica Stued. by Zoysia tenuifolia (L.) Merr.], sprigged at a rate of 36.6 m 3 ha −1 on a USGA‐specified green, to compare grow‐in rate and qualitative turfgrass characteristics. Fertilizer treatments included 1.2, 2.4, 3.7, or 4.9 g N m −2 wk −1 , and a one‐time application of polymer‐coated urea (PCU) at 39.1 g N m −2 , with each N rate coinciding with four N/K fertilization ratios: 1:1, 1:2, 1:3, or 1:4. Visual measurements of grow‐in rate were generally similar within cultivars with 2.4, 3.7, or 4.9 g N m −2 wk −1 There were no significant effects for turfgrass growth or quality among N/K treatments. The 2.4 g N m −2 wk −1 rate was considered best for rapid establishment of all cultivars. Although 1.2 g N m −2 wk −1 amended turfgrass was slower to establish, this rate provided a more desirable putting surface and further decreased the potential for nutrient leaching.