I am trying to figure out what is killing my lawn. The pictures below were taken a few days ago.There is only the one area of this occurring and the yard is about 1/2 acre. The dead area has been growing since last year. It seems to have grown most over the winter and once the snow melted the moss started to appear as well. I have a lawn maintenance company (TruGreen) treat the lawn regularly. They planted seed in the prime growing season last fall, but it did not take.

dead spot overview

moss close up

dead close up

UPDATE At the request of @bamboo I added some pictures from further away as well as picture of a "clean" area of the yard.

farther away

other side

white stuff

normal area

  • 1
    Where do you live? What is your climate normally like, and what has the weather been like recently? Do you know what type of grass was planted?
    – Niall C.
    Mar 30, 2016 at 17:55
  • Is it my imagination, or do the dead areas of grass have a rim of brighter, greener grass compared to the rest of the lawn?
    – Bamboo
    Mar 30, 2016 at 18:01
  • Ever seen any toadstools or mushrooms in the grass? Can you please take a pic from further away as well - I'm looking for colour differences in the area
    – Bamboo
    Mar 30, 2016 at 18:08
  • @NiallC. I live near Pittsburgh, PA. The climate it temperate, warm summers, cold winters, and lots of rain (I think second only to Seattle). Weather has been all over place the last month; snow on the first day of Spring, but in the 70s by Easter. The problem has been growing for about 9 months though. Not sure what type of grass but would hazard to say perennial ryegrass.
    – Skooba
    Mar 30, 2016 at 18:10
  • @bamboo I am seeing what you are now too... didn't notice that before. I will take some more pictures today and update when I can.
    – Skooba
    Mar 30, 2016 at 18:11

2 Answers 2


Looks like snow mold to me. Did you pile your snow there after scooping it off the patio? Did you fertilize with high nitrogen last fall before the snow? No problem...you will have to 'scrape' the dead grass off down to the soil. You can do that with a weed wacker. Rake up the dead grass and dispose. Rake up and soften the top of the soil then reseed. Cover LIGHTLY with soil (not peat moss, too acidic) perhaps an 1/8 inch. Walk all over it this one time. Only fertilize when the rest of your lawn is fertilized. Rope off these areas so dogs and people stay off. Keep these areas moist until the grass gets 3-4" tall then mow. Train these new grasses drought tolerance by watering deeper and allowing to dry out until established grasses and new grasses have the same root depth. Then water deeply 4-6" deep and allow to dry before watering again. Should get you back to once a week watering of 1" (use a kitty food can to check for depth of water)...do not water until your footprints on the lawn stay down. Seriously. Fertilize with organic slow release fertilizer 3X per year. Make sure you do not use a fertilizer with high nitrogen as your winter application (the first number should be less than the second and third numbers for the formulation). To allow vegetative growth with high nitrogen as your last fertilizing of the year makes very weak and susceptible grass to snow mold. Check the pH of your lawn soil...it should be 6.5 to 7.0. If lower than 6.5 you need to lime. Use slow release fertilizer, organic...you'll pay a bit more, use less and see a slower greening of your lawn. Which is a very good thing. Dr. Earth's Lawn Fertilizer just amazed me...and aerate once per year. Mow no shorter than 3" I am kidding you not!

  • Thanks for the great answer. However, the patch started in late summer. The lawn was fertilized (unsure if it was high nitrogen), aerated, and seeded in late September. Is your diagnosis still the same?
    – Skooba
    Mar 31, 2016 at 22:49
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    chuckle...with the new photos it must be whatever chemical was used to clean your patio! Have you ever seen a female dog pissing on a poor lawn? And then that spot is bright green? Conversely have you seen the same on a healthy lawn? Too much nitrogen burns the lawn and one gets dead spots. What have you done to clean that patio? Was it newly installed? Major acids are used to clean a new patio and/or a patio with iron stains from fertilizers. Not so great for the lawn. Easily fixed just watch the chemicals...
    – stormy
    Apr 1, 2016 at 22:02
  • 1
    late summer I would reduce the nitrogen that is so very necessary for grasses during the growth season...need to know the other chemicals...Bamboo was right on! Do you have a maintenance company for your landscape? They HAVE to have notes of the chemicals used, when they were used, what the conditions were when they were used...they should also be concerned, very concerned if dead spots were forming...hummmm.
    – stormy
    Apr 1, 2016 at 22:06

I think its worth your looking at the link provided under Graham Chiu's comment, and watching the Youtube video link within it. It might be cultural mismanagement, Large Patch disease (if you have warm season grasses) or Brown Patch disease, but my money's on a disease or infestation, or a combination of both. Given you're paying a specialist lawn company to take care of your lawn, I'd be getting in contact with them and making a fuss - whoever they're sending out to do the work has not noticed or bothered to do anything about the problems you're experiencing, and I think it's time they sent out a more well informed person from their team to examine the turf. If its Large Patch disease, high nitrogen feeding makes it worse, and I still can't think of an explanation as to why some of the grass is beautifully green and other parts are not - uneven application of feed, possibly? There's even a stripe of brighter, lusher green showing in your fourth photograph in the middle of what appears to be normal grass which has not been affected by disease. And whilst some areas around the paving are bald, which might suggest something's washing off the paving, other areas are not - there's a strip of green between the paving and the bald areas, or healthy grass. Either way, you're paying them, and they're not doing their job properly...

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