Lawn thinning browning
Dear Sir/Madam, Experiencing late summer thinning and discoloration of grass on our front lawn (please see photos attached). Treated entire lawn for bare brown patches (mostly side and backyard) with common lawn insect treatment granules earlier in summer. Thought it might be grubs. This seemed to solve the issue where the complete brown patches existed. Applied Scott’s turf builder and fertilizer and lime spreading late Spring. Other than shade don’t know what issue with thinning might be. Lawn seems to have had plenty of rain (and a little watering). Any suggestions appreciated? Thanks
Grubs do not eat damaging amounts of roots in the spring, so that was not the problem. Spring problems are more often fungal. A grub product would not have helped with a fungus. Often a fungal disease does not kill the roots, just the top growth, and so the grass grows back. (Incidentally, fungal problems are encouraged by early spring fertilization. Avoid that. Fall is the best time to fertilize. If you miss that, fertilize half strength in May.)
The dead patches you see now are probably caused by drought. Most of Howard County has had insufficient rainfall--drought--for about 6 weeks. Plants like about 1" of rainfall a week. It's impossible to know how much rain your lawn gets unless you have a rain gauge. We recommend that homeowners get one (an empty can works fine). But, much summer rain comes from thunderstorms and they are so spotty that it's impossible to know how much rain you've had based on weather reports.
We'd recommend overseeding your lawn this fall. Late summer/ early fall is the best time to overseed your lawn. Here is a very thorough fact sheet about that: http://extension.umd.edu/sites/default/files/_images/programs/hgic/Publications/HG102%20Lawn%20Estab...
Watered lawns actually attract Japanese and other beetles when they are laying eggs, and consequently can encourage grubs. It's normal and not a problem to have a few grubs in your lawn, and we do not recommend using a grub control product unless you are sure you have a real problem because those products are damaging to the other beneficial ecology of your lawn soil. A "real" grub problem means there are about a dozen grubs per square foot, and the only way to determine that is by digging up the sod.