Heat Stress

In the video below Dr.Wendy Gelernter  explains what happens in turf plants when they over heat. At Porter Valley we have two types of turf at risk of over heating. The first and most important is Poa annua ,a cool season grass, found on our greens, green surrounds, tees and  fairways during winter and spring, and  in shady areas. In the video Dr.Gelernter discuses cool season grasses but does not mention Poa annua even though Poa annua is the most common turf on greens in coastal California. In most areas of the country Poa annua is considered very undesirable because of its susceptibility to heat stress. In the video Dr.Gelerner  mentions cool season grasses suffer when temperatures exceed 90 degrees for a few hours. Two weeks ago temperatures at Porter Valley exceeded 102 degrees on  three consecutive days resulting in almost no damage to our greens. Healthy greens under these high temperatures is only possible with a healthy root system and an adequate supply of water. To insure healthy roots green  are aerified every three to four weeks during summer months and irrigation is increased. The Poa annua growing in the other areas of the golf course do not receive the same  intense maintenance as the greens and do not survive  as well as the Poa annua on the greens.  The other cool season turf at Porter Valley is the Rye grass used to overseed tees and fairways. Most of the thin off color turf along the fairway edges is heat stressed Rye grass. As the weather cools in the fall the Rye grass will recover and fill in.

The following United States Golf Association video explains why greens need to be hand watered.
Generally speaking we hand water greens in the morning before play. However as temperatures reach the one hundred degree mark we do some hand watering of greens and green surrounds during the day.