# Help with math.



## Jeff_MI84 (Sep 28, 2020)

Today I put down 0-0-50 at a rate of 1lb/ 1k. The backyard was 5.51lb total. I made two passes total, but had .30lb leftover.

So if I actually put down 5.21lb total, what is the best method to calculate lb/ k and total weight? I'm not the best at math.

The only thing I can think of is to divide 5.21 by 5.51 which is .945.


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## Mightyquinn (Jan 31, 2017)

What's the square footage of the backyard?


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## Redtwin (Feb 9, 2019)

5.21lbs/4.556 = 1.14 lbs of product per 1000sf 
1.14lbs * .50 = .57lbs K per 1000sf

Edit: Whoops! I went off of your profile. Replace the 4.556 with whatever the size of your treated area divided by 1000.


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## Mightyquinn (Jan 31, 2017)

Redtwin said:


> 5.21lbs/4.556 = 1.14 lbs per 1000sf
> 1.14lbs * .50 = .57lbs K per 1000sf


That's assuming the sq/ft he has posted is his backyard, I'm assuming it's for his whole lawn.


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## Jeff_MI84 (Sep 28, 2020)

@Mightyquinn the backyard is 2,756sqft.


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## Redtwin (Feb 9, 2019)

Jeff_MI84 said:


> @Mightyquinn the backyard is 2,756sqft.


In that case, your original math is correct.


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## Redtwin (Feb 9, 2019)

Total applied / 1000sf treated = product rate per 1000sf
product rate X analysis = N, P, or K per 1000sf

so

5.21 lbs / 2.756 = =1.89 lbs of product per 1000sf
1.89 X .50 = .945 lbs K per 1000sf


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## Jeff_MI84 (Sep 28, 2020)

So it's just 5.21/ 2.756= 1.89/ 2 (since it's 0-0-50)= .945 which is .95lb/ 1k correct?


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## Jeff_MI84 (Sep 28, 2020)

@Redtwin and @Mightyquinn thanks gents. It's amazing, I can get an A in business mathematics, but get a D- in fertilizer math. 😂


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## Mightyquinn (Jan 31, 2017)

OK, I think I figured this out

2,756 I'm going to round up to 2800 sq/ft

5.21/2.8(sq/ft)=1.86 lbs of product per M

1.86 x .50(what's in the bag)=.93 lbs of Potassium per M(1,000 sq/ft)

Someone check my math as I need this peer reviewed


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## Redtwin (Feb 9, 2019)

Jeff_MI84 said:


> So it's just 5.21/ 2.756= 1.89/ 2 (since it's 0-0-50)= .945 which is .95lb/ 1k correct?


That is correct. I would have never thought of the 5.21/5.51 method... you're thinking out of the box!


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## Redtwin (Feb 9, 2019)

Mightyquinn said:


> OK, I think I figured this out
> 
> 2,756 I'm going to round up to 2800 sq/ft
> 
> ...


I'm not sure I'm qualified to be considered a peer but it looks correct to me.


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## Mightyquinn (Jan 31, 2017)

Oh yeah, next time just put the rest of the .3 lbs of whatever you have left over on the lawn, no point in putting it back in the bag for that small amount.


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## Mightyquinn (Jan 31, 2017)

Redtwin said:


> Mightyquinn said:
> 
> 
> > OK, I think I figured this out
> ...


You are getting close to me on the post count for whatever that is worth :lol:


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## Jeff_MI84 (Sep 28, 2020)

@Redtwin I wasn't thinking outside the box, I was thinking way out in left field. In the Marine Corps, I had a Staff Sergeant who called me "the dumbest smart kid".


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## Jeff_MI84 (Sep 28, 2020)

Since this was my first fertilizer app I did on my own, is it fairly common to have to make two passes?


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## Redtwin (Feb 9, 2019)

Mightyquinn said:


> You are getting close to me on the post count for whatever that is worth :lol:


That's just because I talk too much. You have 2 year of TLF experience plus all the time on that "other forum" the preceded TLF, plus all your 82nd time. I think you have most of us dominated.


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## Redtwin (Feb 9, 2019)

Jeff_MI84 said:


> Since this was my first fertilizer app I did on my own, is it fairly common to have to make two passes?


It's actually better to do it in two passes if you can get it figured out.


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## Mightyquinn (Jan 31, 2017)

Redtwin said:


> Mightyquinn said:
> 
> 
> > You are getting close to me on the post count for whatever that is worth :lol:
> ...


A broken watch is right twice a day


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## Jeff_MI84 (Sep 28, 2020)

@Redtwin that is a relief. This may sound OCD or just plain odd, but before I loaded up the spreader, I got my tape measurer out and calculated distances, swath distance, when to drop/ raise the edge guard, etc.


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## Jeff_MI84 (Sep 28, 2020)

I forgot about sulfur content. There is 18% sulfur in the bag.

So in that case, it's basically just:

5.21 lbs / 2.756 (backyard) =1.89 lbs of product per 1000sf
1.89 X .18 = .34 lbs S/ 1000sf.


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## Redtwin (Feb 9, 2019)

@Jeff_MI84 That looks correct to me.


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## Jeff_MI84 (Sep 28, 2020)

@Redtwin


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