Last September, at the end of a relatively mild summer, I visited a golf course in Western Japan and saw that the creeping bentgrass greens had failed during the summer, despite being fertilized with products from a well known company. Once that program was stopped, and the focus was changed to supplying the right amount of nutrients to the turf, using cheap fertilizers, the greens rapidly improved, and at the end of this summer, a much hotter one, the greens are perfect. Additional modifications to the maintenance program, specifically in the management of soil moisture, have also contributed to the much improved conditions.
The most important thing about turfgrass fertilization is ensuring that the turf is supplied with the proper amount of nitrogen. When temperatures are at an optimum for creeping bentgrass, it may use about 3 grams of nitrogen per square meter per month. When temperatures are at an optimum for bermudagrass, it may use about 4 grams of nitrogen per square meter per month. These are approximate values that produce a suitable growth rate for golf courses in 2012.
The second most important thing about turfgrass fertilization is ensuring that the turf is supplied with the proper amount of phosphorus and potassium. The requirement for phosphorus and potassium can be determined by soil testing. In many cases, those elements – especially phosphorus – will be at such high concentrations in the soil that they do not need to be added as fertilizer. And for potassium, we can eliminate any chance of a deficiency just by applying potassium at half the rate of nitrogen. Add any more potassium than that, and it will not be used by the grass.
It's that easy. For more information about turfgrass fertilizer and nutrient requirements, see: