This past month’s temperatures, once again, have been above average. In July, the average high is 79 but we have experienced an average of 83, that’s a 4 degree increase. With an increase in temperatures, plants need more water and need it more frequently in order to stay alive. A too hot or too dry weather pattern can be a bad thing for turfgrasses. Turf “wilt” can occur when restricting the turf too long from water. Wilt damages, thins and browns the leaf tissue which will then expose the crown of the plant to the sunlight and heat forcing the plant into a dormant state. Dormancy is the plant’s defense mechanism which allows the turf to slow its growth in order to preserve carbohydrates for survival.
Another common issue associated with dry and/or hot weather is localized dry spot or “LDS”. LDS can occur any time of the year but becomes more evident during long periods of high temperatures. LDS, or what some have called “the brown spots”, is caused by an organic coating that disallows water molecules to adhere to the soil particle. The result is a soil becomes hydrophobic, thus cannot “hold” water. LDS appears as patches of dormant or dying turf grass. The soil beneath the spots will be powder-dry to a depth of 1 to 2 inches. After a rainfall of 1” or less, the turf’s appearance will usually improve, but only for 2 or 3 days.
|Pictured above is a fresh cut cup in #9 green. This is an example of LDS and how cut and dry |
(no pun intended) it can appear.
LDS appears for many reasons including:
- Long periods of hot and dry conditions
- Insufficient irrigation sprinkler coverage
- Thatch (main culprit in fairways)
- South facing slopes
- Areas compacted by heavy traffic (another culprit due to carts)
- Open sun areas
- Heavy clay soils
- Shallow soil
To combat LDS, we use products called soil surfactants, or “wetting agents” to help wet the soil. Wetting agents allow us to water more efficiently, and more effectively. Over the course of the season, we have made applications of wetting agents to our greens, tees, and fairways. We will continue our methods of applying wetting agents along with handwatering dormant spots and aerifying areas (only with extreme LDS). In the long run, our continued cultural practices (topdressing, brushing, verticutting and aerifying) on greens, tees and fairways will help minimize the annually occurring “brown spots.”
|As you can see the “brown spots” in the fairways have already started to recover. Notice the grooves from the verticutting performed this past spring. The turf was able to recover and spread because of the removed thatch from the verticutter.|
On a positive note, our bentgrass has survived the heat wave in great condition. Pictured below, is our cup cutter showcasing 7”+ roots taken from #5 green. With roots this deep we will be able to keep providing great playing conditions until the end of the season.