We are getting calls with people concerned about the “brown areas” in their lawns. The first areas to suffer drought stress are curbs and any areas near heated surfaces like sideways and driveways. Also, large hardwoods like oaks are in full “suction mode” now that the spring rains have ended and the soil profile is dry. They are beginning to use the water that turf needs closer to the soil surface, and large areas will dry. Also, areas with poor topsoil mixed with rock. The “I CAN’T BELIEVE LAWN IS DRY WITH ALL THE RAIN WE HAD THIS SPRING, is no longer valid. Air temps up but humidity is still lower than usual, so there is NO MORE spring rain water left in the root zone for your grass.
Symptoms: FULLY HYDRATED TALL FESCUE HAS GREEN COLOR WITH FLAT LEAF BLADE! Dehydration onset in FULL sun on tall fescue looks like someone drained the fertilizer and turf yellows as chlorophyll evacuates leaf blade! As fescue starts preparing for DROUGHT the leaf blades roll inward to conserve water and the GRASS LOOKS “skinny with rounded blades“. THIS WOULD BE THE IDEAL TIME TO WATER, BEFORE GRASS TURNS BROWN. If grass has already browned, you cannot recover it with your “normal” irrigation schedule. The browning indicates the soil profile within the root zone is parched, and will repel water unless profile is soaked. Put a cup out and water until you catch a minimum of 1inch. Do it 2 consecutive days. Once you have rewet the soil profile, as you can assess by pushing Phillips head screwdriver into soil. Actually, try that in brown areas before you water, but don’t break your wrist! Once profile rewet, please let surface dry for 24-48 hours. Turf will recover from drought stress if you rewet soil profile! What we DO NOT want to do is to keep surface wet by daily water, which will feed the nutsedge and encourage “brown patch” If you are NOT on a slope, and can figure out how to keep your grass green by DEEP, INFREQUENT irrigation, it will reduce nutsedge and fungus development SIGNIFICANTLY this summer.
1. Stages of leaf moisture
2. Tree in full “suction mode” drought stressed turf
3. Example of how fescue looks in some sunny areas BEFORE leaf roll begins. Pre stress chlorophyll shutdown = Dark green fescue areas can yellow before leaf rolling begins.