Under extreme high temperature conditions – when the temperatures reach the upper 90’s and above – the grass plants will begin to shut down as a defense. In some cases such as with annual bluegrass they often die in a relatively short period time. One of the most important things you can do as a turf grass manager is to try and cool the turf. The best way I know is by a light application of water to create evaporation cooling. If you have an in ground irrigation system this means turning the system on to give you approximately .05” of water. You do not want to flood the turf at this time because you can create scald and cook the grass plants. The timing of this water application ( in this case called syringing) should be just before the hottest time in the afternoon. When I was a golf course superintendent we would begin this around 2 PM.

Have you ever noticed that sometimes no matter how much water you apply to your field that it only soaks into the top half inch or less. The top thatch acts like a sponge but the water is not getting through to the soil beneath. Ample aeration will assist in keeping this from occurring but once it happens the only thing I know that will assist in alleviating this condition is the use of soil penetrants. These compounds can be applied in the liquid or granular form. They reduce the evaporation of water by allowing the water to penetrate into the soil more readily. There are some that work better in sandy conditions and some better with clay and believe it or not some work on all types of soil. Look into this – you will be glad you did.

As a sidelight – remember that good fertility is a great aid in the best utilization of water by the plant. A good example of this is to observe the green spots that come about where pets urinate on an under fertilized field.