I think it's fertilize. The neighborhood dogs do a great job on my lawn since I live on a corner.
I use Scotts with Halts crabgrass preventer in the spring, then 6 weeks later a liquid Ortho spray that hooks up to the garden hose that knocks out weeds - especially those pesky dandelions. I've found the spray to be much better than the granular, as long as you avoid rain.