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Every adult has at least one “lawn person” in their social circle, and there’s a reason Lawn People are so obsessed: There are few things in this world that require more care and planning than a lawn. Lawns are thirsty, hungry time vampires that turn brown and brackish in a heartbeat if your attention wavers. The thing about grass is that it has to be mercilessly tamed, and that involves mowing on a regular basis so it doesn’t get any ideas and grow wildly as nature intended. But if you think that grass is grass and that the mowing schedule used on one lawn can be easily applied to any other lawn, you’re sadly mistaken. There are a lot of different varieties of grass out there, and how often you need to mow your lawn depends on what kind you’re dealing with.
How high grass should be before you cut it
As a general rule, you should let your lawn grow a bit—unless you’re absolutely certain your grass is a type that thrives when cut close, resist the urge to cut it too short. Keep in mind the “one-third rule”: Never cut more than a third of your grass height in a single mowing session. Once your lawn is established and growing, the frequency of mowing depends on how high the grass gets. First, find out what kind of grass you’re dealing with. Most lawn grasses will fall into one of two basic categories:
Cool season grasses
If you live in the northern parts of the U.S., you’re probably dealing with fescue, bluegrass, or ryegrass. These grasses grow quickly in the spring and fall, and will accelerate if there’s a lot of rain. Ideally, mow fescue (which has wide blades and a shiny look) when it’s 2-3 inches high, bluegrass (which has V-shaped blades) when it’s between 2 and 2.5 inches (note that bluegrass can grow up to 2 feet high if you don’t tend to it), and ryegrass (which has narrow blades and a lighter green color) when it’s 1-2 inches high.
Warm season grasses
Bermuda grass, zoysia grass, Buffalo grass, and St. Augustine are classified as warm season grasses. Mostly found in the Southwest U.S., these grasses thrive in hot weather. They grow quickly in the heat, but often don’t fare well if there’s a cold snap. Like their cold-weather cousins, heavy rains will encourage faster growth. Bermuda grass is coarse, stays pretty low to the ground, has above-ground roots and needs to be trimmed when it’s between 1 and 1.5 inches high. Buffalo grass is softer and more flowing, and you need to let it grow out a little more—cut when it’s about 2 inches. Zoysia is a lighter green, but maintains its color longer—cut it aggressively, when it’s between three-quarters of an inch and an inch long. St. Augustine is a popular choice because although coarse to the touch, it forms a dense carpet—you should let it get above 2 inches before you cut it down.
What is a shade lawn?
You will sometimes hear reference to “shade lawns” that imply this is a whole separate category of grass. It is and it isn’t—a shade lawn is generally a cool season grass that has been carefully mixed and engineered to thrive in low-sun conditions. They can be fussy lawns to grow for obvious reasons, so if you’re trying your hand with shade grass, let it grow out a bit longer than you otherwise would before mowing.
The unknown
If you inherited a lawn and have no earthly idea what kind of grass you’ve got (and don’t feel like doing the necessary research to find out, or replacing it), just follow the aforementioned one-third rule and mow about once a week. This will probably maintain most lawns; if your grass starts to yellow, let it grow out a bit more, then resume your schedule.
