With the above-average precipitation we had in spring and early summer, it kept the grass lush, but that has also contributed to some of the current turf issues. Since the consistency of the rain stopped and temperatures kept rising, we are seeing more issues in full-sun areas than in partial shade.
While cool-season grasses are struggling a bit right now, summer weeds are in their glory. The pre-emergence herbicides applied in the spring are depleted. Microbes in the soil breakdown leading to the development of summer weeds like crabgrass. Perennial weeds also thrive in these conditions—like yellow nutsedge. Multiple fungicide applications are often necessary.
Inconsistent moisture and warm-hot weather also lead to more fungal disease problems. These cool-season grasses tend to recover, but it just takes them a little longer. This year, more root fungal pathogens have developed. Depending on the severity, some lawns will recover; others will need seeding to assist with the recovery.
Avoid watering in the evening; it allows the grass to remain wet longer than normal and gives disease more fuel.
Consider bumping up the cutting height of the mower a notch to conserve a little soil moisture.
Fertilize moderately to maintain nutrient levels but not over stimulate growth.
Schedule core aeration for your turf—as September is an excellent time to do this. With the heavy rains earlier in the year, it has caused more soil compaction. Lawns need air exchange in the root zone to help recover. Fall fertility will be essential to create new growth to mend any decline that occurred during the summer.