Lawn problems

Question: Up until late last year, we had a pretty decent back yard.  It is mostly shady.  Mid to late summer we noticed thinning and bare spouts developing and before we try and "repair" the lawn we are trying to figure out what the problem is.  Thank you for any insight you can give us.

responder: Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied May 26, 2023, 11:18 AM EDT
response: A shady site isn't conducive to a thriving lawn, unfortunately, so that might be a contributing factor to consider. As trees mature (if they are what is casting the shade, which appears to be the case here, as opposed to a building) they will shade their surroundings more thoroughly, and the root system also competes more with the surrounding turf. The soil in the photo also appears to be poor in that it looks dry, probably compacted, and potentially also low in organic matter content.  We recommend that areas not conducive to turfgrass growth be converted to lawn alternative plantings (or even just a mulched area if you prefer). If you are keen to keep growing turfgrass in this area, you can browse our extensive web information for lawn care and maintenance, though a good first step is to have a laboratory soil test performed if you haven't done one in a few years. This will assess the organic matter content, acidity (pH), and relative levels of most key nutrients. (Note that any marked as "excessive" in test results doesn't imply it's a problem that needs addressing. Rather, it indicates that adding more of those particular nutrients via fertilizer will have no benefit for the grass because the soil levels are already plentiful.) We can help you to interpret the test results if desired.  If this lawn is cool-season (tall fescue, usually), then the ideal time of year to overseed is in late summer to early autumn. Liming that might be needed can be done around the same time, as is the first application of fertilizer. The soil test results will point to whether you need a regular (in Maryland, legally, this means a formulation with zero phosphorus [P]) or starter fertilizer (allowed when test results show low P levels). There are charts for application rate and timing for this and warm-season lawns (zoysia) in the linked content above. We also have pages about liming, core-aerating to reduce compaction, and irrigation to lessen any drought stress on the turf. Note that once seed is sown, turfgrass seedlings must be monitored closely for watering needs as they do not tolerate drying out once germination has occurred. Fine fescue is the turf type most suitable for shadier sites, but its care is a bit different from tall fescue in that it's mown much less, fertilized less, and is less tolerant of foot traffic.  If you are open to alternative groundcover plantings, there are a variety of perennials and low-growing shrubs that are suitable for mostly-shade locations. Depending on how well the soil drains and whether is skews wet or dry based on weather, and depending on if deer browsing is a regular issue, the list of candidates can be narrowed-down a bit to make it less overwhelming. We are happy to make some starter suggestions for plants once the site conditions are described, though we can't produce an exhaustive list.  Certain turfgrass diseases can cause patchy or scattered dieback, but these tend not to appear this early in the season (if these pictures are recent and not from last year). Information about lawn problems from insects (less likely), diseases, and other factors (non-living, environmental conditions) can be found in our lawn content online library as well.  As to why the damage seemed to have appeared relatively quickly or suddenly, it's hard to say. It's possible underlying stress factors were present the entire time and didn't produce noticeable symptoms, but a more recent stressful event (the mini-drought most of the state was experiencing through the first part of this year, for instance, or a heavy rain event that didn't drain fast enough) or cumulative soil compaction from foot traffic pushed the turf over the edge of its tolerance in those spots, resulting in die-off. If a pesticide or fertilizer was applied in recent weeks, maybe the dosage was too high or an overlap in application passes accidentally over-dosed certain patches. Heavy or repeated foot traffic use by people or pets can also wear-down turf and its tolerances, even though it's one of the most traffic-tolerant groundcovers, contributing to root dieback from reduced soil oxygen due to the compaction. In addition to that, in that scenario, root moisture fluctuations can compound the issue as compacted soils don't absorb water as readily once dry and also don't drain excess water as readily when wet. These are all educated guesses as possible factors involved here as once turfgrass has died out it can be difficult to diagnose what the original issue was.  Miri

responder: The Question Asker Replied May 26, 2023, 2:08 PM EDT
response: Thank you for your thoroughness and your time!  Sent from my iPhone  On May 26, 2023, at 11:28 AM, Ask Extension <<personal data hidden>> wrote:    ﻿

responder: The Question Asker Replied May 29, 2023, 2:20 PM EDT
response: I am not sure if the pictures I sent gave enough of what is happening in both the front and back yard.   I have ordered a soil test kit from Univ of Delaware and will send that in.   In the meantime, I have attached pictures showing the overall condition of the yard.  THe last 2 pictures are of the backyard.  The first one is of the front.   We have been in this house 23 years and our lawn normally looks very good even if somewhat thinner in areas of shade.    If you have any other suggestions, I would greatly appreciate it.    Allan

responder: Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied June 01, 2023, 4:05 PM EDT
response: Hello Allan,  Thank you for the additional photos. Seeing the mature tree and pattern of dieback, we agree with our original assessment that growing conditions are what is stressing the turf most. Shade from the tree in summer, plus competition with most of its root system, coupled with soil compaction from the foot traffic that traverses the area, are all combining to cause the grass to struggle. As to why it seemed sudden when the tree is clearly long-established and no significant changes seem to have been made to the landscape, it's hard to say, but perhaps a tipping-point was reached in the past few months (like the dry weather pattern mentioned previously) that the grass couldn't tolerate as well. We can help you interpret the soil test results when they are ready if you wish.  For now, you may want to plan on overseeding this autumn using a tall fescue blend that includes at least one of the recommended cultivars (more than one cultivar would be great, but probably very hard to find). That way, you can be assured that it's as disease-resistant and heat-resilient as possible. The current Recommended Turfgrass Cultivars publication is linked here but you may see it updated to the 2023 version by the end of summer as the ongoing testing/ranking results are released.  If you haven't already, you might want to irrigate the lawn periodically as recent rains have been scattered and generally insufficient to alleviate the current abnormally-dry weather patterns. Feel the soil around four or more inches deep and water well if it's somewhat dry to the touch. How often this will be needed depends greatly on weather and soil type/drainage but as a generalization, one soaking a week in hot, dry weather is usually sufficient. You don't need to keep the grass from going dormant (doing so might worsen its vulnerability to stress, actually, plus use too much water), but keeping the roots alive and minimally-stressed in terms of soil moisture will set it up for good regrowth come autumn. Plus, when seed is put down later, irrigation patterns need to change for the short term to less-saturating but more frequent because germinating seed is very vulnerable to drying out until it's established (having reached mowing height once or twice). Although overseeding now might have some success, it's harder to achieve given the warmer weather, greater need for irrigation, and competition with weed seeds that will take advantage of the opportunity to germinate as well.  If you opt to irrigate using a sprinkler or hose sprayer, try to either avoid hitting the nearby boxwood foliage, or water early enough in the day so that the leaves can be fairly dry by nightfall. This is helpful in avoiding conditions for certain leaf infections (both for boxwood and other plants), as fungal and bacterial spores often have an easier time infecting foliage that has wet surfaces.  Miri

responder: The Question Asker Replied June 01, 2023, 4:41 PM EDT
response: Thank you for all of your information, time and detail!  I greatly appreciate your help! I will forward you the soil test results as soon as I receive them.  Allan

responder: Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied June 01, 2023, 7:29 PM EDT
response: You're welcome!