Weed and Feed for the lawn.
My wife wouldn't let me use any chemicals on the law, afraid that we would track it into the house and the dog would lick it up off of the floor and get sick.
I used to pull crabgrass, and weeds by hand, and sprinkle in some Kentucky blue seed, for hours at a time. One year I didn't keep at it as much, and the following year, it really got ahead of me. Soooo... I picked up a bag of weed and feed, and one day when she and my daughter were going to be out for the day, I ran down to my friend's house and borrowed his drop spreader.
The unit was frozen with rust, so I freed it up with WD-40 of all things
Then I got to business... pushing the feeder in one direction, moving it over one row, and pulling it back, moving it over one width and giving it a push, then over again and pulling it back.
When I covered the front lawn, and returned the unit in better condition than when I borrowed it.
A couple of weeks later there was something wrong with my lawn. There were swaths of 6 inch grass, and swaths of 4 inch grass!
Apparently the drop spreader doesn't work when you pull it, but rather, only when you push it.
There was a significant difference in the fertilized swaths, compared to the unfertilized swaths.
I therefore conclude, that weed and feed works!