So I'm using the lawn log that was supplied in the stickied post and I have a question about the calculations. I did not change any formulas but it seems that my lb/k is high? Per G-man's post in my other thread he said not to go over 1 lb/k per month. It's calculating 3.11 n/k.
For reference this is the product I used. Menards Crabgrass Preventer
. I used a 15k bag (51lbs) and a 5k bag (17lb).
It's not clear if you already applied, and what you based application rates on (the spreadsheet, the bag label, your experience...).
I'm sure G-man will be along later to address that specific spreadsheet and how it works. But going by the label and my experience with Dimension, I can help you address the application rate issue.
I like to go for the 4-month rate usually, so that would be around 4 lbs/K of product. That way it's wearing off by mid to late August so if I have to seed it's no problem. I just don't deal with lbs of AI per acre unless I really have to. It's not how I think, because I'm not dealing with acres.
If using a product with lots of Nitrogen like the one you're using, I like to split this up into 2-3 smaller applications spaced out over time, say 4-6 weeks apart. It allows more efficient use of the fertilizer.
Anyway, at the 4 lb/K rate, it would take 80 lbs of product over 20K area.
Back to the rate question. Again, I'm not going to interpret your spreadsheet, but I do know that in order to get 3 lbs/K of N on the ground, you would have had to put down 11.5 lbs/K of product...
Obviously you didn't do that...because you used 68 lbs of product over 20K area, right?
That equates to the 3.4 lbs/K rate, which is just under the rate I use, but still a pretty decent rate that will last for a while.
At 3.4 lbs/K of product, you put down just under 1 lb/K of Nitrogen.