The Waste Management Phoenix Open was a tremendous success and ended in an exciting playoff finish. This tournament often marks the unofficial start to the golf season in the Southwest, but it also provides a signal to prepare for the next big event, which is of course transition! Yes, it’s only early March, but recent trips to desert golf courses reveals that the understory bermudagrass is already pushing up new shoots and therefore consuming carbohydrates stored from the fall. Dr. James Beard taught that the bermudagrass plant will produce three or four new shoots from stored carbohydrates when emerging from dormancy. If those new shoots are unable to produce new food due to competition from the overseeded ryegrass, the bermudagrass plant will eventually die. This process is occurring right now!

Begin the transition process now by thinking about four key elements to improve bermudagrass recovery from overseeding:

1. Sunlight – Lower mowing heights on all overseeded tees, fairways and roughs. By mid-March heights should be at or below 0.5 inch on closely mown turf and at or below 1 inch in rough areas. Continue to lower rough mowing height and consider scalping rough in April to 0.35 inch. For more on this strategy, read the USGA article “Rough Transition.” Courses are also encouraged to use light-intensity vertical mowing to slowly thin the ryegrass canopy.
2. Water – Typically the slowest areas to transition are the driest. Maintain adequate soil moisture on overseeded areas from April through the end of June. Consider using a soil moisture meter to quantify wet and dry areas and manage accordingly.
3. Chemical Assistance – Utilize one of the “transition chemicals” such as the sulfuronurea herbicides, penoxsulam and pinoxaden. In recent years, much success has been found using two or three applications at low rates to yield a slow, progressive transition from ryegrass to bermudagrass. 
4. Fertility – Approximately two weeks following chemical growth regulation of the ryegrass, begin to increase nitrogen fertility. This timing will avoid undesirable growth of the ryegrass while encouraging the understory bermudagrass.

The transition season is always a tenuous time for golf courses in the desert southwest, but experience has proven that a proactive program that starts early in the spring is the best method to deliver a good-quality golfer experience from ryegrass to bermudagrass.

Best wishes during the 2020 transition season and please do not hesitate to contact the USGA Green Section West Office for more information on these strategies or any other agronomic practices.