Mow when your turf is four inches high
Wait any longer and you'll shock your grass, slowing its growth.
Raise the mower deck to three inches
Tall grass stays greener and shades the soil, preventing weeds from germinating.
Note how fast the grass grows
Mow when your turf needs it, not by your calendar. In the spring, when grass grows faster, you might do it twice a week but in the summer, twice a month.
Which mower is best?
If you have a small yard, choose a walk- behind, mulching rotary mower that minces cut blades so they break down and release nitrogen to the soil quickly. Buy one that adjusts to mowing heights of one to three inches. (Old-fashioned push-reel mowers are kinder to the environment, but most don't trim grass higher than two-and-a-half inches.)
If you have one or more acres, choose a ride-on mower with eight to 13 horsepower, or for more muscle, go for a lawn-and-garden tractor with 16 to 20 horsepower and mulching blades.