What is good grass fertilizer?

Fertilizer will have numbers on it, three usually that represent the nitrogen, potassium, and phosphorous content of the fertilizer, referred to as the N-P-K numbers.

The first number represents the nitrogen content, the higher the number there the " hotter " the fertilizer will be IE: the higher the number there the more growth you will get, and the higher probability for fertilizer burn if applied too liberally, this nutrient is responsible for growth. Next comes Phosphorous, it helps build great roots, after that comes Potassium, this builds strong cell walls.

The best fertilizer will ba a balanced- slow release fertilizer with a good micro nutrient package. I suggest a balanced 10-10-10.

What this means is that each of the elements mentioned above makes up 10% of the bags contents, so in a 50 lb bag, 10 lbs are nitrogen, 10 lbs are phosphorous, and 10 lbs are potassium, the remaining 70% is inert matter such as the clay particle the fertilizer was attached to during manufacture, or the slow release coating applied to give an extended feeding period.

The brand doesn't really matter once you have this information.