SPECIAL TOPICS: HOT SPOTS

“Hot Spots” are areas of the lawn that are suffering from water stress caused by any one of a number of phenomenon. Many people assume these areas are just areas that are not getting watered. To be sure, if you have a sprinkler system, you should first check that these areas are getting good sprinkler coverage by visually inspecting the sprinkler system in operation in the affected area. Be sure to check rotor type heads to see that they are actually moving the full pattern.

If you are sprinkling the area completely, and still have discolored or brown areas, you have “Hot Spots”. “Hot Spots” are primarily observed in the hottest part of the day, and are characterized as being irregularly shaped areas in the full sun portion of the lawn where the grass has begun to wilt. Wilted St. Augustine grass blades will fold up flat in order to conserve water, causing the thatch layer underneath to become more visible giving the area a brownish, straw-like look. If the wilt gets severe enough, the grass blades will get a grayish color, and roll up in a tube to further conserve water. After this stage, if special attention is not paid to the stressed areas, the grass will die.

When the problem occurs in certain areas of a lawn, it is because these areas may have a little bit more naturally occurring thatch than other areas of the lawn. Maybe the soil is slightly more porous in the affected area. Sometimes the sprinklers don’t get quite as good of an overlap in these areas. Soil compaction will decrease water penetration and cause “Hot Spots”. Concrete and other manmade materials will capture and radiate excess amounts of heat causing one area to dry out faster than another. The area may also have a very slight pitch that causes a portion of the irrigation water to run off. “Hot Spots” always occur when the weather is hot and breezy and after an extended period without rain usually between April and July. Regardless of the cause, there is only one solution. MORE WATER!

Increasing irrigation system watering duration and frequency can help with “Hot Spots”; however, special watering of the effected areas is the most efficient way to deal with the problem. Hose watering with a small shower type sprinkler for an hour will often rewet the area and eliminate the “Hot Spot”. Several waterings of a shorter duration are prefered over a single longer application of water. Keep in mind this area has become super dry, and the sand and organic matter in this area has very likely become so dry it is actually repelling the water, so it will take at least one and maybe several slow waterings to get the area rewet. For flat areas of the lawn you can simply run the hose at a slow trickle in the center of the area for an hour and achieve good results.

As soon as the “Hot Spot” is rewet, the grass will assume its normal color and growth within a few days.