# Soil temp range for final fertilizer app?



## NJ-lawn (Jun 25, 2018)

I know we app when top growth stops but is there a range of soil temperatures we can also use to help us decide when to apply?

I assume it's in the 30s?


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## g-man (Jun 15, 2017)

At 32F for sure the top grow stopped, the root grow likely stopped.

The best way is to mow weekly until you noticed no more clippings.

Or, just don't do the final one. Research keeps pointing out how pointless it is.


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## ericgautier (Apr 22, 2017)

> Cool Season Grasses (Fescue, Bluegrass, Ryegrass):
> 90F Shoot growth ceases
> 77F Root growth ceases
> 70F Maximum temperature for root growth
> ...


^^ saw this somewhere.


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## ericgautier (Apr 22, 2017)

g-man said:


> Or, just don't do the final one. Research keeps pointing out how pointless it is.


I might skip it this year.


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## NJ-lawn (Jun 25, 2018)

Thanks guys..... wow that's interesting. I wish I had the will power to skip it but I love doing final app.


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## MMoore (Aug 8, 2018)

NJ-lawn said:


> I know we app when top growth stops but is there a range of soil temperatures we can also use to help us decide when to apply?
> 
> I assume it's in the 30s?


Never assume.
I measured my soil temps to be 50F in the sun and 48 in the shade last night. My location is likely quite a bit higher than you too, but I know that doesn't always matter.


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## NJ-lawn (Jun 25, 2018)

MMoore said:


> NJ-lawn said:
> 
> 
> > I know we app when top growth stops but is there a range of soil temperatures we can also use to help us decide when to apply?
> ...


Well according to that chart there's a window of 33-40 degrees. That's a decent size window.


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## g-man (Jun 15, 2017)

The chart has an issue. At what depth are you measuring vs the temperature in the chart?


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## Green (Dec 24, 2017)

Personally I drop when growth stops and/or 4-inch temps are consistently 40 or lower.


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## rockinmylawn (Mar 25, 2018)

is there a general temperature delta rule of thumb between air temp vs. in ground temp?
Like 50° air temp = 58° below ground.


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## g-man (Jun 15, 2017)

Not really. Too many variables(wind, density of turf, spring vs fall, moisture).

This website provides soil temps at from 0-10cm. There are other networks with 0-2, 0-4, etc. http://www.greencastonline.com/tools/soil-temperature


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