Most fertilizer companies understand that a green lawn is their primary selling point. Giving you green is their money in the bank.
What is wrong with that? We all want a dark green lawn, right?
They know most homeowners know nothing about what their grass needs or when it needs it or even the rate their spreader applies. For example, most homeowners, if they only fertilize once a year will fertilize in the spring. The fertilizer for cool season grasses often comes in formulations such as 32% nitrogen, etc. It is easy to over-fertilize and people often apply twice what is needed in spring. You get green grass that has to be mowed three times a week for a while. Too much nitrogen pushes growth at the expense of the grass. But the fertilizer company gave you a green lawn where people are often delivering 1 lb of nitrogen per 1000 sq. ft.
In reality, the spring fertilization only calls for about 1/2 a lb of nitrogen at most. The goal in spring is to replace the nitrogen used during the surge growth. 3/4 of the total nitrogen applications are applied in the fall for cool season grass, not spring.
On our site, we give the mathematical formulas to make it simple. Regardless of what the nitrogen content of the bag says, you can put down the exact amount you need. Click on the link below for more information on fertilizer rates.