Annual dead grass areas

Question: Good afternoon!

I hope you had a good lunch and maybe are ready for cup of afternoon coffee, iced tea or lemonade that you can enjoy my tale of dead grass, below!  I’m hoping you can help me figure out what’s going on with several areas of my lawn.

I am a self-taught lawn care homeowner.  I have built two healthy lawns from two different soils (alkaline clay soil 1991-2010); acidic sand soil 2010-2012) that each had only scattered tufts of grass at the time we bought the home.  The process was different for the two lawns, but I used soil amendments (fertilizer, lime, compost, manure) for each and an annual grub control in the front yard of the 1991-2010 home (two beautiful river birch trees were a constant magnet for grubs).  Each yard’s development including aerating, thatching, and seeding with regular cutting and high mower settings from mid-June to mid-October.  And I had two beautiful lawns.

In 2012 we bought and moved into our current home, our first-time purchase of a new construction home.  As part of our new home construction, the builder sodded the entire property with good quality turf.  Since then, I have continued all of my normal lawn care practices (no thatching needed) with very good to excellent results… for the most part.  And so I write today.   

For the first five or six years, the lawn was essentially healthy with only a few areas where new grass needed to be planted; essentially a typical lawn situation.  Then about six years ago, a number of patches of grass began dying each year on both sides of our concrete driveway.  I repaired each in early October by removing all of the dead grass, adding new topsoil, fertilizing, seeding, covering with straw and watering.  During this same six-year period, the rest of the lawn has been fine, with normal brown spots and dormancy during extreme heat and droughts and then recovery with only small annual losses.  And each year, my lawn repair work has been rewarded with a bounceback with the lawn looking great by the end of the fall and then as in the new year as spring and summer came along.

But something’s not right with these areas next to the driveway (and about four or five spots next to the foundation).  At first I thought that the condition was from relatively immature grass roots in these areas and their inability to survive extreme summer heat.  But after I few years of repeated dead grass in the same areas, I thought that there might be objects below the surface that was stunting root growth.  So in 2020, I tested the dead  grass by driving a metal spike into multiple spots in each area and discovered MANY large rocks, large pieces of splintered lumber, a couple water bottles, an 18”x6” log, and a couple sections of PVC pipes.  

So I tried again in 2020 and was rewarded with great growth in the fall, a nice start in the spring and… the same dead areas by mid-August in 2021… and again in 2022.  Now this year, with the drought, the same dead areas hit d in mid-June.  I am at a loss and need some help.

My first thoughts are, this fall, to remove ALL of the grass from the drive-way to two feet out, on both sides and then plant new grass.  I’m thinking I may discover a lot more construction waste.  But I really don’t know if this will resolve the situation.  The odd thing is that none of this “condition” is spreading.  It’s confined to the areas that I have planted and replanted and replanted.

Thanks for taking the time to read this.  I hope you can help me solve this puzzle!

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 30, 2023, 12:37 PM EDT
response: These are interesting symptoms, having the dead grass blades be so darkened, and we are consulting plant pathologists and turf specialists for suggested culprits. We will get back to you as soon as we have their feedback. In case they are tied-up today, a reply might not arrive until mid-week or later next week due to the holiday.  We agree that an abiotic issue (something not caused by a living organism like a pest or disease) may be the main problem given that it is restricted to the same areas each time symptoms reappear. You may indeed find more construction debris or other obstacles to drainage or moisture-holding capacity in the soil if you were to dig that area out more (again), because this is not uncommon, though you don't necessarily need to go through that effort just yet. Still, if buried debris is present, that alone might not explain why the lawn seemed to be fine in those areas for several years post-sodding only to have this issue arise afterwards and then keep recurring. Stress from drought or an excessively-rainy year on top of soil drainage impediments could be part of an explanation, though we don't think the same weather patterns resulted in the same degree of stress in each of those successive years of dieback.  When you overseed in autumn (we presume this is a fescue lawn and not zoysia), are you using a high-quality seed mix that contains one or more of the recommended turf varieties? (Granted, they are sometimes hard to find, and it's rare to find a mix that includes more than one as the top-performer list is always changing since testing is ongoing.) We ask because these varieties are locally trialed and should be among the most resistant to typical turf disease issues plus our weather stress of high summer heat and humidity.  Have you had a laboratory soil test performed in recent years? If not, it might be useful to do so this season, not necessarily for this specific problem but so you know if any adjustments to acidity (pH, via lime) or nutrient levels (fertilizer formulation) would help improve the vigor of the lawn overall. We can help you to interpret the test results if desired. These labs do not screen for pathogens, pests, or abiotic contaminants (spilled pesticide, pollution like oil leaks from a mower, etc.) that might be contributing to dieback.  As another piece of information for the diagnostic team, have you been irrigating the lawn at all this season? If so, about how often or for how long? Do these areas sit near or downhill from a roof downspout outlet? While the current drought impacting Maryland overall means we haven't had lots of infection-promoting rainfall, some areas have had scattered rain showers that might be contributing just enough moisture for the development of some diseases. How regularly the turf foliage is getting wet may help us narrow-down what pathogens (if any) could be responsible for this dieback.  Lastly, we see some irregularly-sized white granules/pellets in one of the close-up photos, close to the soil surface. Are these a pesticide, and if so, what was applied and around what time of year?  Are you able to share some photos of any lesions on otherwise-green grass blades that might be appearing adjacent to or near, but not within, these dead zones? We think we see a few brown-tipped grass blades in the photo taken from a greater distance, but can't zoom-in with enough clarity to see detail.  Miri

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 July 06, 2023, 12:44 PM EDT
response: Thank you for your patience. We are still investigating this with one of our turf experts (who might be swamped with a variety of tasks but who should be available soon to touch base with us). In the meantime, any information you can provide regarding the questions we asked previously would be helpful. Additionally, have you noticed any mycelium (the fuzzy or web-like mass of fungal filaments atop the soil or turf itself) appear near the dead zones either on mornings after a heavy dew or after a rainy day? If so, photos of that would also be helpful as they might point to a disease different from the most common summer lawn ailments. We have linked to one example of mycelium pictured on our Brown Patch page, though the appearance of mycelium looking like that doesn't necessarily mean that specific fungus is responsible.  Miri

responder: The Question Asker Replied July 10, 2023, 9:53 AM EDT
response: Good morning Miri… and all!    Thank you for this detailed and sincerely appreciated response from July 1st---and the follow-up from Thursday (7/6).  I will respond to your comments and questions sequentially.    Paragraph #1: With most of the lawn rebounding after the drought (pictures attached) but these same, almost identical, spots being completely dead, I am leaning more and more to the idea that there is indeed still more construction debris or large rocks (every landscaping project involves finding massive amounts of rocks at an almost hard-to-believe level.  I created a 4’x8’ vegetable garden six years ago and the space produced a full wheelbarrow of rocks!).  When I tested these dead areas three years ago by driving a spike into the dead spots, I didn’t anything.  BUT---there were areas near, and removed, from these spots where I did find debris and new grass grew and has stayed healthy.  These spots, as I indicated, have been growing and dying year after year for about five years.    P#2: I have overseeded with the same seed in all areas of the lawn using Scott’s Sun & Shade mix and all other areas have filled in nicely.    P#3: I submitted a soil sample for a soil test four years ago.  At the time, I was confused by these same dead spots and actually for the first time in my life hired a long care company to look at the lawn and then contract them for an annual fertilizer program for 2 ¼ years (Q4 2019, 2020, & 2021).  The soil sample indicated that my soil was nicely balanced and would only need a lime amendment once every 3-4 years.  This same company showed me the “spike test” for discovering ONE possibility for poor growth and led to finding quite a few places that were struggling because of large rocks (6”-12” long), chunks of wood and other construction debris.  I stayed with them for those two years but realized that I was doing as good a job or better on my own.    P#4: I don’t generally water my lawn much except when there is young, vulnerable seed or plants.  For the most part, I accept the course of mother nature and don’t try to win that battle.  That said, I will water to reduce stress… to a point.  Again, when I see that we are in a long dry spell as we just were, I let nature take its course.  And as you can see from these pictures taken yesterday (Sunday, 7/9), the lawn has bounced back.  Although I didn’t send you our drought-condition lawn, it was “normal”: lots of brown spots or generally brownish areas and all of those have bounced back.  It was… and is… the gray grass that went from green to brown to gray quickly and is clearly dead.    P#5: I wanted you to see those white spots because I think they could have been mold spots.  I keep a schedule for my fertilizer/lime/grub treatments and there had been no fertilizer on the lawn for at least four weeks.  That particular picture was the only area where those white spots appeared and those same white spots are now gone.    P#6: I have attached pictures of the grass immediately adjoining these dead areas.    And finally on your follow-up email from this past Thursday: no I haven’t noticed any mycelium on any other areas in the lawn.    Thank you, again, for your time and your interest.    Best regards,    Jeff

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 July 10, 2023, 5:06 PM EDT
response: Hi Jeff,  Thank you for the follow-up information and photos. Our plant pathologist, based on the appearance of the initial photos, suspects Pythium, a type of root rot caused by fungus-like organisms, even if obvious mycelium on the surface of the patch edges hasn't been evident. (Pythium is quite common in the landscape so by itself this is not unusual.) That said, you certainly might find (more) construction debris in the soil of those problem spots, and this impact on drainage could have exacerbated soil conditions that favors the development of a Pythium infection.  While we are not recommending a chemical treatment for the Pythium because it couldn't cure existing disease, if you proceed with your plans to dig-out that area, look for debris to remove, and replant (perhaps after amending with some compost or good-quality topsoil), the improved soil conditions should help reduce the likelihood of it returning in the future. You could then lay fresh sod or seed if you prefer, though it's probably better to wait to do that until early autumn at this point when cool-season turfgrass will be easier to establish. You did mention not finding any obstacles there before when probing with a spike, but maybe the obstruction is a bit deeper than that. Our pathologist recommends checking up to 18" down, at least for more major debris (like a piece of plywood or large chunk of concrete, for instance), if you're amendable to that degree of effort.  The product used to overseed might not have contained any of the locally-recommended turfgrass cultivars, though admittedly it can be challenging to find one that does (or at least using more than one of them). Local seed vendors focused on the Chesapeake region probably do include one or more of those trialed varieties, which have been tested for disease resistance, among other attributes. We don't keep track of the myriad grass seed products for sale in our area but you can compare the variety list that should be included on the bag (or on a sticker on its packaging) with the page we linked to previously about the recommended cultivars. (This year's list probably won't be published until August or so, and we'll update our website links to the new document once it's available so the link address will stay the same.)  The white pellets in the prior close-up photo don't look like mold, so we don't know what they are if you didn't apply any type of fertilizer, lime, or pesticide recently. You could always cut into a couple (if they reappear since they're now gone) to see if they're spongy and soft like mold growth would be, or harder like the pellets of a type of fertilizer or other product. Maybe they dissolved, if you've received enough rain to green-up the previously-stressed lawn.  We see that the cut ends of the grass blades look pretty ragged, and the wounding from dull mower blades can increase the turf's vulnerability to pathogen infection. If possible, mower blades should be sharpened (or replaced) a minimum of once a year; twice is better. If it's been some time since your mower blades were checked, this might be good to do prior to the autumn lawn care season when mowing becomes a little more regular again.  Miri

responder: The Question Asker Replied July 11, 2023, 9:11 AM EDT
response: Good morning Miri,    Thank you so much for this additional information.  And based on what you’ve written---and what I’ve… endured!...---I’ll plan on digging up these areas in early fall.  And I’ll dig much deeper!  : ( No fun.  But definitely something I need to do given this ongoing problem.  If I find some buried treasure, like a big piece of plywood, I’ll take a picture and send it to you!    And thanks also for the recommendation for a blade sharpening.  It’s been over two years and I’ll get this done now, as you’ve suggested.    Thanks again.    Jeff

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 July 11, 2023, 10:12 AM EDT
response: Hi Jeff,  Sounds like a good plan -- good luck! If you wind-up having repeat issues with the lawn there (or anywhere else in the yard), this would be a good candidate area for considering lawn alternatives.  Miri