# How do foliar treatments figure in to nitrogen totals?



## Fronta1 (Jul 11, 2017)

Obviously, your putting a fraction of what you would with granular but it's also absorbed at a very high rate, so I need some help on how to do the math using the npk numbers to find out how much n I'm actually applying. Thanks


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## GrassDaddy (Mar 21, 2017)

I may be wrong but I thought it was absorption speed that changed not amount. Kinda like slow release vs fast.


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## Fronta1 (Jul 11, 2017)

GrassDaddy said:


> I may be wrong but I thought it was absorption speed that changed not amount. Kinda like slow release vs fast.


So you're sayin if I put down a gallon/1k that's the same as a pound/1k?


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## Fronta1 (Jul 11, 2017)

Or would it be 8lbs/1k since a lb is 16oz and there are 128oz in a gallon?


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## Fronta1 (Jul 11, 2017)

I just looked it up. (Love it when I answer my own questions) You're right, its the same, you just have to convert lbs to gallons, which is about 8 lbs/gal, depending on how thick it is. Thanks.


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## RockyMtnLawnNut (Jun 23, 2017)

I think you're forgetting one important thing, and that is the concentration of nitrogen that is in your foliar spray. Applying 1 pound of Nitrogen dissolved in one gallon over 1000 square feet would yield a different result than applying 2 pounds in one gallon over 1000 square feet. This is a really interesting question actually, and it made me go look up a few articles. I'm certainly no expert, but here's what I found:

-The maximum amount of foliar nitrogen that was going to be taken up by bentgrass greens in studies was taken up within the first four hours. After that, you could basically wash the leaves off with irrigation, thereby washing the rest of the N off of the leaves
-The foliar nitrogen seemed to have a higher absorption rate in more relatively humid climates. They postulated that when the droplets dried, they were no longer available for absorption.
-There is a maximum amount of N that can be absorbed, and a maximum amount that can be applied before turf injury occurs. The recommended amount appears to be in the range of 0.1 lb of N/1000sq ft. 
-Urea seems to be the most preferred choice of N source to mix in a foliar spray
-The amount of N actually measured to be absorbed by the turf was between 30-70% 
-There are no current head to head studies comparing root absorption by Nitrogen salts vs. foliar sprays

Here are some articles for your viewing pleasure:

http://gsrpdf.lib.msu.edu/ticpdf.py?file=/2010s/2010/100107.pdf

http://www.usga.org/course-care/how...pplied-nitrogen-applications-21474860541.html

http://journal.ashspublications.org/content/117/1/75.full.pdf

Thanks for bringing this up. I think it would be awesome to have a better understanding of how to possibly incorporate this better in a home lawn setting. It appears that the more frequent applications of lower rates of fertilizer (spoon feeding) act almost like a slow release fertilizer, feeding the turf steadily over time. It's just that you're controlling when the release happens.


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## ABC123 (Jul 14, 2017)

I've had this discussion before, was told this shouldn't count towards total N for the year like soil applied.


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## RockyMtnLawnNut (Jun 23, 2017)

ABC123 said:


> I've had this discussion before, was told this shouldn't count towards total N for the year like soil applied.


That would seem logical since the amount being applied is so low. Even if you applied the recommended 0.1 lb N per thousand every other week, it would take ten weeks to put out one total pound of N.


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