Fall Update
As fall approaches growing conditions for much of the turf showing signs of stress will improve. Turf growing on the golf course can be classified as either cool season or warm season. The Kikuyu grass found in fairways and rough and the Bermuda grass found on tees are in the warm season group. These grasses prefer daytime temperatures above eighty degrees and night temperatures over sixty. Warm season grasses perform best April through October. As fall temperatures drop growth of warm season grasses slows. As winter temperatures drop lower Kikuyu grass and Bermuda grass will stop growing losing their green color turning straw color. Growth will start again in March as temperatures increase.
The grass Poa annua found on our greens, green surrounds, tees, fairways and rough are in the cool season group which prefers daytime temperatures less than eighty-five degrees and night temperatures in the forties. Rye grass growing around greens ,on tees, in fairways and in the rough though more heat resistant than Poa is also in the cool season group.
The natural growth pattern for Poa is for seed to germinate in the fall grow through winter and spring then die as the temperatures exceed ninety degrees. Maintaining healthy Poa during summer months is only possible through intense maintenance usually limited to greens. Greens aprons do not receive as intense maintenance as greens and show significant stress by late summer as we have seen this year. In an ideal transition from overseeded Rye grass or naturally occurring Poa the warm season grass will grow and fill areas faster than the cool season grasses die off. On the majority of the golf course transition takes place without notice. Unfortunately the longer cool season grasses survive into summer the poorer the transition will be. What is commonly seen, as failure of Poa and Rye grass in late summer on golf courses through out southern California is actually cool season grass dying off as programmed by Mother Nature. Areas around the golf course where cool season grasses are showing stress have been fertilized to encourage Kikuyu grass and Bermuda grass to fill in. Areas around greens have been overseeded with Rye grass to cover the bare areas.
Many Los Angeles residents are unaware water use restrictions have not been lifted. Golf courses that purchase potable water from Los Angeles Department of Water and Power have a monthly water allotment. If a golf course exceeds their allotment three times in one year the golf course will be restricted to irrigating only three times a week. August was one of the hottest months on record with thirteen days over one hundred degrees. Irrigation was increased during August because of the extreme heat which resulted in receiving our first warning for exceeding our allotment. Most of the turf damage this summer is related to water restrictions.
Getting the correct amount of water on the entire golf course is a very difficult task. Unfortunately irrigation systems do not distribute water evenly. With the best irrigation system other factors such as wind, slopes and trees effect water distribution. There are many soil types found through out the golf course ranging from fine clay with great water holding capacity to soil made up of course sand and rock the size of bowling balls that hold very little water, and sand stone that neither water or roots can penetrate. With a typical nights watering in summer of .25 inches of water clay soil will be wet for a couple days where a sandy gravel soil two days later may have dead grass due to drought. These factors do not take in to account huge shifts in weather that occur along inland foothills. To eliminate all dry spots would require increased irrigation, which would result in increased wet spots. Sense most golfers find wet areas more of
a annoyance than dry areas, our irrigation goal is to have far fewer wet areas than dry areas.
