There is no one perfect or absolute best fertilizer to purchase for your lawn, but there are many good ones available. Nitrogen is the most important nutrient; percent nitrogen is expressed as the first number in the series of three on the fertilizer bag.
http://extension.illinois.edu/lawnfaqs/fertilizing.cfm
Contrary to what some people think, the more you water your lawn, the more fertilizer it needs. With more water, there is more growth, so you need more fertilizer, Turnbull says. If you have a sprinkler system, you'll need to fertilize about every six weeks.
http://www.popularmechanics.com/home/lawn-garden/how-to/g237/the-quick-and-easy-guide-to-fertilizing-your-lawn/
Milorganite 36 lb. Organic Nitrogen Fertilizer is good for promoting healthy growth of lawns, trees, shrubs and flowers. The non burning formula doesn't have to be watered-in. It is fortified with 4% iron to help produce thick, green lawns without excessive growth. It doesn't contain any salts, so it is good for use in drought conditions. 1  Use on lawns, trees, shrubs and flowers to promote healthy growth.  36 lb. bag covers 2,500 sq. ft. to feed your lawn or garden from corner to corner.
http://www.homedepot.com/p/Milorganite-36-lb-Organic-Nitrogen-Fertilizer-100048741/100618523
Know the Numbers. When you buy fertilizer, you'll see three numbers on the label. These numbers show the percentage of nitrogen, phosphate, and potassium, respectively, which are the primary nutrients needed to feed your lawn. So a 20-5-10 bag will have 20 percent nitrogen, 5 percent phosphate, and 10 percent potassium.
http://www.popularmechanics.com/home/lawn-garden/how-to/g237/the-quick-and-easy-guide-to-fertilizing-your-lawn/
1 If you are using a complete lawn fertilizer, it should have a nitrogen-phosphorus-potassium (N-P2O5-K2O) ratio around 4-1-2 (For example 16-4-8).  Use a complete NPK fertilizer when planting a new lawn. Established lawns rarely need phosphorus fertilizers and should only be used when recommended by a soil test.
http://www.better-lawn-care.com/best-lawn-fertilizer.html
Balanced fertilizers, such as a 10-10-10, have a N:P:K ratio of 1:1:1. The reason these are not suggested for repeated use on lawns is the amount of phosphorus applied, when supplying the one pound of nitrogen per 1,000 square feet, becomes quite high.
http://extension.illinois.edu/lawnfaqs/fertilizing.cfm
A good place to start is by having your soil tested. A soil test is a helpful tool. It will tell you the percentage of organic matter, available nutrients and the pH of your soil. You can then pick the best lawn fertilizer and add soil amendments based on soil test results and recommendations.
http://www.better-lawn-care.com/best-lawn-fertilizer.html
Contrary to what some people think, the more you water your lawn, the more fertilizer it needs. With more water, there is more growth, so you need more fertilizer, Turnbull says. As the grass grows, it uses more nutrients.. If you have a sprinkler system, you'll need to fertilize about every six weeks.
http://www.popularmechanics.com/home/lawn-garden/how-to/g237/the-quick-and-easy-guide-to-fertilizing-your-lawn/
Choosing The Best Fertilizer Based on Cost Per Unit of Nutrient. Fertilizer costs per pound of nitrogen is an important factor to consider when shopping for the best lawn fertilizer. Comparing two products - Product A and Product B: Your lawn is 15,000 ft2 and you want to apply 1 pound of nitrogen per 1,000 ft2.
http://www.better-lawn-care.com/best-lawn-fertilizer.html
1 Use on lawns, trees, shrubs and flowers to promote healthy growth. 2  36 lb. bag covers 2,500 sq. ft. to feed your lawn or garden from corner to corner. 3  Apply granules during the growing season to encourage a rich, green lawn and strong plants.  Keeps feeding for up to 10 weeks, so you don't have to constantly fertilizer.
http://www.homedepot.com/p/Milorganite-36-lb-Organic-Nitrogen-Fertilizer-100048741/100618523
what is good fertilizer for grass
Nitrogen, Phosphorus, and Potash fertilizer is a good fertilizer for grass. An NPK fertilizer is good fertilizer for grass.