# Can someone help me do math? Calculating #N



## ColeLawn (Nov 11, 2020)

I need help calculating #N when applying _liquid_ N/fert.

So, assuming I applied 3oz/1k of *Lesco 12-0-0*, how much N did I put down on ~650sf this weekend? 
_--Label rate is 2-5oz/1k_

Also, the label says to apply with 3-5gal of carrier. I only have a 2gal sprayer, so I only used ~2gal of carrier. I haven't seen any negative effect from not using enough carrier. I can't say I have seen any effect at all though. My plan is to apply 12-0-0 weekly alongside Milo at bag interval/rate, so I'm trying to dial in the numbers. I understand that this is pretty much just an iron app. My soil test showed that my macros/micros were high and the recommendation was nothing but N this year.


I have the 2.5gal jug, and I believe it is 28# net weight, but I can confirm that if you'd like


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## bhutchinson87 (Jun 25, 2018)

You don't need to worry about the amount of nitrogen when spraying just a few ounces for the benefit of getting some color from the iron. However, the math is below:

2.5gal jug at 28#
320oz at 28# (128oz/gal)
320oz with 3.36# of N (12% nitrogen of 28#)
1oz = 0.01# of N

So, if the label rate is 2-5oz/M then that is 0.02-0.05#N/M. This number is negligible when thinking about the amount nitrogen being applied to the lawn.


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## lawnphix (Apr 13, 2019)

Yeah, these products don't deliver much N at all. Great breakdown @bhutchinson87 .

If you do apply a true liquid fert (like CoRoN) and need help calculating the N, I have some calculators that can help with the amounts.


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## ColeLawn (Nov 11, 2020)

@bhutchinson87 and @lawnphix, thank you both for the breakdown and math! I guess I was not far off in my calculations.

So, say I was targeting .25#N/1k/bi-weekly, it's definitely *NOT* recommended to put down 12.5oz/1k of 12-0-0 every week, correct? What I'm trying to get at is, is this product pretty much just to be used as a color/iron booster? How would I supplement something like CoRon 28-0-0 (or other true liquid ferts) with 12-0-0? Or would you not use both?

I'm trying to avoid putting down any nutrients that I don't need based on soil test recommendations. It would be so much easier to just throw down some 10-10-10...I was looking for CoRon but it was out of stock at DMO, so I went with the 12-0-0 because I was impatient. I know there's 46-0-0 but with my yard size, granular apps can get kind of tedious and spraying is just a lot more fun and efficient.

I guess I'm back at the drawing board...help wanted! At least I'm only out $39.99 on the 12-0-0 :lol: Worthy experiment, I guess.


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## corneliani (Apr 2, 2019)

That 12-0-0 is not a bad product at all but it's really a Chelated Iron product and not necessarily a pure Nitrogen source. The N in the jug is meant to drive the micronutrient uptake & photosynthesis process more than anything.

If you want more N consider getting a bag of their soluble 46-0-0 urea and melting it into this spray mix. That bag should only run you about $30 +/-. They sell the NOS version now that has nitrification inhibitors built in for a more efficient application.


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## ColeLawn (Nov 11, 2020)

@corneliani So would it be frowned upon to spray 46-0-0 and 12-0-0 biweekly, at the same time, assuming I am targeting .25#N/1K/biweekly out of the 46-0-0 alone?


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## corneliani (Apr 2, 2019)

ColeLawn said:


> @corneliani So would it be frowned upon to spray 46-0-0 and 12-0-0 biweekly, at the same time, assuming I am targeting .25#N/1K/biweekly out of the 46-0-0 alone?


If you had a Bermuda lawn I'd say it sounds just about right. For a cool season .25# of foliar N seems way high in the heat of the summer.


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## g-man (Jun 15, 2017)

For this lawn size, DEF (diesel exhaust fluid, yes from walmart auto part section) would be a good option. It is urea + pure water.

10oz (300mL) = 0.1lb N.


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## ColeLawn (Nov 11, 2020)

@corneliani My last fert/iron app was going to be Milorganite at July 4 weekend.

I thought .25#N/bi-weekly in spring and fall is pretty standard practice...?

@g-man The DEF would replace the 12-0-0? Or could I throw down 125oz/week? :bandit:

Update: SiteOne was able to locate a 50# bag of 46-0-0 (non-NOS) for me and it should be in by the end of the week.


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