# Weak grass



## Hieronymus (May 22, 2018)

I have got patches of weak grass (prg). It's light green, it won't bounce back after mowing and there are even patches turning brown. Ph is 7.5, it's moist and recently got fertilised and I already checked on grubs, temperatures are good around 20 degrees Celsius. What could this be?


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## Suburban Jungle Life (Mar 1, 2018)

Can you take close up pics of the blades and the stems near the dirt? Shooting off the wall, could be fungus, triv, needs iron, LDS...


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## LawnNeighborSam (Aug 14, 2018)

Summer die off? Were those areas heat stressed at one point and died slowly?


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## LawnNeighborSam (Aug 14, 2018)

Shade spots?


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## Green (Dec 24, 2017)

Yes, first make sure it's PR and not something like Triv.

If it is PR, I've seen PR that is light green in my own lawn, when the rest is dark green. Not sure why. But it does exist.


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## Hieronymus (May 22, 2018)

It's certainly prg. It's not a fungus. And it's in the sun voor about 8 hours a day. And it's not a summer die off because it's new grass that I overseeded about 5 weeks ago, and the summer has come te an end over here.


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## Suburban Jungle Life (Mar 1, 2018)

If you're certain it's PRG, then it may be deficient in some nutrient. Might need some N or some iron. Have you done a soil test in those areas and compared it to the other healthy areas?


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## Hieronymus (May 22, 2018)

Started this topic last season. And I am seeing a pattern. Every time I use iron the grass plants get weak. The strange thing is that I have iron in some of my fertilizers that don't have this effect on the grass. What could this be. I use 200 gr in 5 liters of water. I use this iron (See image)


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## Wolverine (Jan 17, 2018)

Does it have stolons? I have had the same issues with my lawn in certain areas, grass that lays down, holds good color until the heat kicks in then dies off. Bent grsss maybe?


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## Hieronymus (May 22, 2018)

Wolverine said:


> Does it have stolons? I have had the same issues with my lawn in certain areas, grass that lays down, holds good color until the heat kicks in then dies off. Bent grsss maybe?


No stolons. Its all the grass that gets weak. Mostly PRG, some bluegrass and a couple of other varieties even the Poa Annua! 😂


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## Suburban Jungle Life (Mar 1, 2018)

Any luck with a soil test yet? Might help get a whole picture.


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## g-man (Jun 15, 2017)

@Hieronymus 200g for the 350sqm? foliar? no Ammonium sulfate mixed in?

I would follow MQ formula in the first post. FAS
I tweaked the formula for easy metric and 100sqm: First mix 100g of AS + 4L of warm water, then add 120g of FE 19,5% . Apply via foliar and let sit for at least 2hr before rain/irrigation.

Please test out the formula in a smaller area first and double check my math. Too much iron will turn the lawn black.


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## Hieronymus (May 22, 2018)

Suburban Jungle Life said:


> Any luck with a soil test yet? Might help get a whole picture.


No particular things from soil tests.


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## Hieronymus (May 22, 2018)

g-man said:


> @Hieronymus 200g for the 350sqm? foliar? no Ammonium sulfate mixed in?
> 
> I would follow MQ formula in the first post. FAS
> I tweaked the formula for easy metric and 100sqm: First mix 100g of AS + 4L of warm water, then add 120g of FE 19,5% . Apply via foliar and let sit for at least 2hr before rain/irrigation.
> ...


I will take this in consideration. The only thing I am worried about with this combination is that the soil will get very acidic.


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## g-man (Jun 15, 2017)

It should not. This is a foliar application with a very low concentration.


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## Belfort (May 21, 2018)

Because of the iron sulfate the toplayer of your soil gets very acid (low PH) especially Perennial ryegrass and poa annua 
don't like the acid shock.


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