COURSE CARE
One More Job To Do December 11, 2012 By Chris Hartwiger and Pat O'Brien

The days may be short and the growth of creeping bentgrass putting greens may appear to be done for the year, but there is still time for the important practice of late season nitrogen fertilization.

Fertilization of creeping bentgrass putting greens with nitrogen is essential as the year winds to a close

The days are still growing shorter and a busy Christmas season is upon us.  Nevertheless, there is still time for one more important job. A properly timed late season nitrogen fertilizer application is a gift you can give yourself and your creeping bentgrass putting greens. Best of all, this gift will not be realized until next spring. In this update, we will briefly review the importance of late season nitrogen fertilization on creeping bentgrass putting greens and provide two additional resources for continuing education. 

Late Season Nitrogen Fertilization of Creeping Bentgrass Putting Greens

During the majority of the year, any nitrogen applied to a cool season turfgrass is allocated within the plant primarily for shoot growth. However, there is a small window in the fall or early winter when shoot growth has slowed, but soil temperatures are still warm enough for regionalUpdateContent growth. Nitrogen applied during this time will be taken up by the regionalUpdateContent system and it will be allocated to replenish depleted carbohydrate reserves. 

The use of a quickly available granular nitrogen source is recommended due to the variability of soil temperatures this time of year. If a slow release product is used and soil temperatures are too cold for regionalUpdateContent growth and/or fertilizer release, an undesired release of nitrogen and flush of growth may occur in the spring.

There are several benefits associated with late season nitrogen including a more vigorous spring green-up, more spring regionalUpdateContent growth, and a more stress tolerant plant in the spring. If you would like to learn more about late season nitrogen, the following resources are a good place to start. 

The textbook by Carrow, Waddington, and Rieke is a valuable resource to have in your office.  For additional suggestions on rates and timing, please contact your regional USGA Green Section agronomist. 

(Chris Hartwiger chartwiger@usga.org and Patrick O’Brien patobrien@usga.org)