Turfgrass dieback can be hard to diagnose, especially from a viewing distance since many symptoms overlap, but we think there are several factors contributing to this situation.

There may be a bit of Brown Patch getting started, which is a very common turf disease once the weather gets warm which tends to resolve on its own. The linked page provides management and prevention tips.

Drought stress is potentially behind some of the struggling areas, at least if the turf isn't being irrigated. Most of last year, Maryland was in drought, and we're already "abnormally dry" again in much of the state. (Less so Cecil County as of today, but that may change soon as the heat persists and the rains are still insufficient.) It's okay if you can't irrigate the lawn, or choose not to for the sake of watering costs, but it can promote earlier or greater dormancy in summer (which is normal for cool-season grasses like fescue). Compacted soils can complicate attempts at watering, since they might not absorb water from irrigation or rain as readily, so core-aerating prior to seeding in autumn may help. Not only does aerating help to reduce compaction, but it boosts seed-to-soil contact, which will improve germination rates. If we remain drier than usual this autumn, be aware that irrigation of newly-sown seed is critical if the weather isn't damp enough, as germinating seed is not tolerant of drying out, so establishment is much improved if the new grass is kept moist until it reaches mowing height.

Is the lawn company performing a soil test every ~3 years or so?  (You can have it tested yourself, if you prefer.) If not, they should, to make sure they are compliant with Maryland's lawn fertilizer law, plus so they are not applying nutrients that aren't needed. A laboratory soil test will assess nutrient levels, acidity (pH), and organic matter content. We can help to interpret test results if desired. If the acidity is too strong, the lab will include lime application recommendations to bring it into the pH range preferred by turfgrass.

Fertilizer can "burn" plants if over-applied and not watered-in, but it would not be expected to injure plants if applied at the correct dosage, especially if a time-release formulation was used, which most lawn fertilizers would probably be. Generally these types slowly release nutrients based on soil moisture levels (at least in part), so if moisture is lacking, they simply wouldn't be releasing much in the way of nutrients yet. Fescue lawns are normally fertilized twice in fall and once in spring (or the spring application can be skipped for healthy lawns), so it's interesting that the lawn company is doing the opposite. Autumn is when fertilization efforts are more impactful.

The photos also suggest that there are a mix of grasses present, which is one reason it looks patchy (some are struggling more than others). While most cool-season lawns are a species mix (mostly tall fescue, plus small amounts of Kentucky bluegrass, perennial ryegrass, and/or fine fescue, for example), there may be some grasses in your lawn that are undesirable. For example, barring severe drought, both Crabgrass and Japanese Stiltgrass remains greener longer into the summer (since they are warm-season grasses) compared to cool-season turf, and Japanese Stiltgrass can also stay short when regularly mown. Both are annual weeds, meaning they die with the onset of winter, but they can recolonize a lawn the following year if their seeds are present in the soil (or if seeds move back in on the wind or wildlife, like deer feet) and any pre-emergent herbicide the lawn company might be using either doesn't target those weeds or is applied too late in the spring. We can't say with certainty that the greener patches visible in the photos are either of those weedy grasses, but it's a possibility given how lush and green they look in comparison.

Some of the completely-brown patches might be fine fescue that was hit hard by fungal outbreaks in spring and is now going dormant for the summer. (Or it died out completely, it's hard to tell.) Fine fescue can be a useful lawn component in semi-shade, but it can have more vulnerabilities than tall fescue, so for sunny locations, the preferred grass would be tall fescue.

There are two options for the rehabilitation of the lawn at this point: you can overseed regularly each autumn, gradually increasing the percentage of the lawn that is the ideal selection of recommended turf cultivars, or you can strip the sod (sod cutter machines can be rented, or a lawn company could do it) and replace it with fresh sod so the turf mix is uniform throughout the lawn. The latter will be the more expensive approach, but will yield the best results since it replaces the lawn entirely. You could also opt to do one method for one part of the yard and the other method for the rest of the yard. Overseeding doesn't always successfully replace any undesirable turf types in an established lawn, in case uniformity of its texture and color is important. If you take either approach, the best time of year to overhaul or augment a fescue lawn is in early autumn.

For now, being summer and the dormant season for fescue lawns, nothing needs to be done except monitoring for watering needs, if only so that the crowns of the turf (the growing point of each plant, which sits at soil level) don't die due to prolonged drought. This will not involve nearly as much watering as attempts to keep it greener all summer (which is purely for aesthetics, since it's not natural for the cool-season grasses to be growing in summer), which is not recommended, even though it is still widely done.

Miri

Hello Linda,

I'm glad it was helpful and not too overwhelming of a response, and you're welcome! Happy summer,

Miri