As I said, it takes more effort than dry fertilizer, but it's less expensive, shows results more quickly and treats the soil, so the benefits are greater in the long run.
Jerry Baker's All-Season Green-Up Tonic
1 can of beer (
not light beer)
1 cup of ammonia
1/2 cup of liquid dish soap (
not anti-bacterial or concentrated, trust me)
1/2 cup of liquid lawn food (get this at a nursery or farmers' supply)
1/2 cup of clear corn syrup
Mix in large bucket, pour into a 20-gallon hose-end sprayer and spray on everything (grass, bushes, flowers) every three weeks. One batch covers approximately 1500 square feet.
http://www.jerrybaker.com
Jerry Baker arrived at this concoction by studying ideal soil and vegetation conditions, then applying it practically in trial-and-error tests to validate its effectiveness. Each component contributes to the overall goal: healthy plants and healthy soil for them to thrive in. I first tried this out about five years ago, and I'm totally sold on it. My grass has dramatically improved since I began using this approach, as well as the following.
Thatch will kill your grass if you don't keep it under control, which isn't terribly hard. Rake the entire yard well (dig the crap out) in the early spring to get all the dead grass and debris out before the grass goes into heavy grownth. Jerry Baker has a good thatch-control tonic on his website.
Keeping your mower blade sharp is extremely important; I sharpen my blade almost monthly. A clean cut seals up faster, which helps the grass retain more moisture. It's also a good idea to mow in the late afternoon or (better) early evening to allow the fresh cuts time to seal before the sun beats down on the lawn.
Using a mulching mower provides a constant source of food for your grass: itself. As was mentioned, keep the weeds under control and make sure the dandelions aren't being fed back into the lawn if you're mulching. Another great advantage of mulching is that the seed your grass produces is overseeding your yard every time you mow.
Never cut off more than 1/3 of the height of your grass. If it's too long, set the mower up and mow it once, wait a couple of days and mow it again at normal height.
Using tools to remove weeds is a good idea, too. I use a monster screwdriver to remove dandelions and their roots. The dandelion is out of the yard, and the hole from the screwdriver aerates the soil.
Pelletized lime is a necessity if you have oak and/or pine trees. Acorns and pine needles are extremely acidic, so you need to get the acorns and needles picked up and neutralize the acid. I work my tail off in the fall and early winter cleaning up the leaves and acorns from two 70' oak trees, but I've seen what happens to the grass the next year if I don't get that all out.