So I explained that we were still in the gray zone, and she needed to be patient. In due time, Mother Nature would take care of business and green things up. Mowing the grass tall, between 2 and 3 inches in height, will take care of crabgrass. The taller grass will shade the surface of the soil, preventing the germination of crabgrass and other weed seeds. That shading also reduces the evaporation of water, which reduces drought stress during dry periods and keeps grass roots cool during heat waves.
Taller grass experiences less stress from mowing, and so it grows at a slower pace.
Taller grass also protects the soil's surface from pelting raindrops that compact the soil. It also helps to deter certain pests, such as Japanese beetles. But to really do the job, it should be applied when the weeds are growing full tilt, so it's best to bite the bullet now and wait until June to do the treatment. Next, we talked about the grub issue. If my friend's lawn does have a grub problem, it won't show up until June when the grubs begin actively feeding on the roots of the turf, and that's the time to do a grub check.