# Light green grass patches, is it poa or something else?



## MachoManMooch (Aug 8, 2019)

Zone
6a

Grass Type
Cool season mix

Issue
Light green grass, possibly Poa infestation from Fall 2018 overseed
Iron deficiency from young grass

Possible Causes
Iron deficiency, particularly on new grass from overseed
Other crop content from seed
(I do not have the label saved, but Execu-turf bags on the shelf this year have anywhere from 0.05 to 0.5% other crop)

August 2019 Soil Test
pH of 7.4, low Phosphorous, high Iron content (due to higher pH?)

Background

In the fall of 2018, I overseeded with Execu-Turf playmaker mix (85% TTTF, 10% PRG, 5% ***) as part of an attempted upgrade to my front yard. The summer of 2018 was brutal with broadleaf weeds and crabgrass. Spring 2019 had a relatively nice green up and I went through a standard process of a split pre-emergent application (Dimension), Fertilization and spot weed control throughout the summer. We had a lot of rain in the spring with moderate temperatures through June.

Once July hit, so did summer and the front lawn struggled a bit but I did not have the weed problem that I had previously. I irrigated enough to prevent full dormancy. I did not fertilize between Jun 15th to Aug 10th. I fertilized with Jonathan Green organic (10-0-1) to get the summer to fall transition work started. In early August, we also had some cooler temperatures arrive and the lawn started to bounce back. The second half of August was cooler than average (Highs 70s and a few days of 85-90). It was about this time that I started to notice the problem.

The particular area that I focused on with my pictures is the biggest concern. I thought it could be a Poa infestation but I thought August would be a little too early for that to potentially pop up. I also had thought it could be due to some iron deficiencies based on my soil test results.

During the first weekend of September, I fertilized with starter fertilizer from Scotts (21-22-10) with tenacity. Within a week or two, the bright green patch and a few other small areas really stood out from the rest of the lawn.

Next steps

I guess my options would be to either kill off, wait and reseed or sod; alternatively I can try to dig out those patches and apply seed or sod; 
​Apply some iron supplements to those specific areas; 
​Pre-emergent to hopefully suppress and more germination, which would then prevent an overseed but I can then deal with it better next year.
​Other options or thoughts?







The grass to the right is the lighter bladed grass (did the best I could to grab a couple)


Front Lawn Overview
​


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## MassHole (Jun 27, 2018)

Following.


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## DIYDad (Sep 12, 2019)

I'm wondering the same thing. I have a few spots like that in my lawn as well. And from the looks of it, both those grass blades you pulled look identical except for color. Not sure if its poa, it might be a nutrient deficiency in that particular are is my best guess, or something under the soil prevent deep root growth or nutrient uptake. Did you probe around in the soil in that spot to see if there's anything funky going on there? Compacted soil, rocky area, etc. Sounds like its mostly centered around the photo and just a couple smaller areas? Just wondering how extensive it is/what percentage of your lawn is light green like that. Your soil tests showed high iron so its probably another nutrient that's lacking. 7.4 isn't too high of ph (I'm up around 8.0).


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## Babameca (Jul 29, 2019)

@MachoManMooch It is not Poa annoa (no signs of seed heads). From the last picture I would rule out Triv as well. The leaf starts dark and lightens up at top. Do you have soil test done. What is your fert programme. What do you use to apply fert. How much water do you apply and how often (measured)


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## tgreen (Oct 20, 2018)

It is not Poa A. If it is poa T then a patch that large should easily lift off the ground. You should be able to roll it up like a carpet. Can you?

The pics don't really look like poa T to me but can't say for sure. Poa T would be very thick and dense with very fine blades at this time of year in your area. I don't see that in pic 1.

More close up pics might help


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## MachoManMooch (Aug 8, 2019)

@Babameca My most recent soil test came back with low phosphorous levels, high iron content in the soil. It does seem like there is some high contents of other micronutrients as well, I don't know if that has anything to do with it.

With respect to fertilizer applications (~1500 feet for that section of front yard) Hopefully I've done my math correctly.

April 16, 2019 application of Jonathan Green 8-0-1 organic; 15 lbs applied, 0.8 lbs N/1000 sq ft
June 4th, 2019 application of Jonathan Green 10-0-1 organic; 15 lbs, 1.0 lbs N/1000 sq ft
August 10th, 2019 application of Ideal Organic fertilizer (Menards) 4-3-0; 22 lbs, 0.6 lbs N/1000 sq ft and 0.4 lbs P/1000 sq ft
September 14th, 2019 application of Scotts Starter with Mesostrione 21-22-4; 8 lbs, 1.1 lbs N, 1.1 lbs P, 0.2 lbs K

I use an Earthway spreader

Soil Test Results


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## MachoManMooch (Aug 8, 2019)

@DIYDad Yea there are a few areas here and there that have some similar colored grass but not as dense of coverage compared to the area I have in the picture. I have some liquid iron from Bonide that I am considering applying just to that patch to see if that changes anything. I'll have to go take a look to see if the soil is any different there relative to other spots in the lawn.

Do you do any type of amendments to your soil, or stick with a relatively routine fertilizer program?

@tgreen Thanks, I'll take a look and see tomorrow if I can pull it up easier/see if I can take some more close up pictures.


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## Babameca (Jul 29, 2019)

@MachoManMooch Stop the organic for a bit. It contains a lot of micros and Calcium and your organic content is already high ( I may suspect you see mushrooms in rainy days). Your pH is 'way' too high and P low (which is easy to explain with all 0 P you applied so far). Don't push more Iron when you have more than needed, it is simply locked in due to the high pH. Start correcting pH. Fertilize with higher P fert. You can't correct pH with higher Sulphur (Ammonium Sulfate) because your S is high too. I would go with X-2X-X fertilizer based on Urea for now. What about watering? Overwatering can make grass lime green. There are other ways to lower pH that you can easily search this forum for. I hope that helps.
B


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## DIYDad (Sep 12, 2019)

MachoManMooch said:


> @DIYDad Yea there are a few areas here and there that have some similar colored grass but not as dense of coverage compared to the area I have in the picture. I have some liquid iron from Bonide that I am considering applying just to that patch to see if that changes anything. I'll have to go take a look to see if the soil is any different there relative to other spots in the lawn.
> 
> Do you do any type of amendments to your soil, or stick with a relatively routine fertilizer program?
> 
> @tgreen Thanks, I'll take a look and see tomorrow if I can pull it up easier/see if I can take some more close up pictures.


I usually do Milorganite twice a year, synthetic fert in the fall, and now just this year I've started using heavy regular applications of humic acid as well. I think I'll be adding kelp to the mix next year as well.


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