While oak is correct, one can't expect an hourly employee
to be an educated individual on all things especially like a turf grass specialist would be.
In todays world a google search would prolly provide more useful information.
But do know a soil sample it the real way to go so one does not over fertilize of one nutrient and under fertilize with another.
Your basic nutrients of NP and K are the staples but micronutrients are also valuable when dealing with certain soils as well as lime to get the soil PH correct if needed.
If your ph is incorrect some nutrients cannot be utilized by the plant.
One of the biggest polluters of lakes/streams is not agriculture, but over fertilization of unneeded nutrients from residential lawns and golf courses.
That is a proven fact.
The other big polluters are waste water treatment plants.
Daddy always said "drink up stream from the heard"