How close can I cut my grass? Depends on the grass

Published 10:30 am Friday, April 3, 2020

Mowing the grass is just not all that important this spring, but at least it won’t impact our social distancing. So we can mow as we await better times for everybody.

Over the years, I’ve harped on mowing height and relayed what folks more knowledgeable than me say about the importance of mowing lawn grasses to a proper height. True, nobody ever killed his or her lawn by mowing it too short once or too short for the whole year. But mowing too short over time offers up potential problems, the three problems most associated with lawn grass: weeds, insects and disease. The odds for any of these increase when the grass is stressed.

There are the natural stresses of drought, heat and cold. But cutting grass too close to its crown really stresses the heck out of it. The crown is the area where the roots and leaves both grow out from above ground stolons and/or below ground rhizomes.

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Sure, the grass almost always recovers, but there are weed species out there that are tougher than grass and will recover faster and outgrow the grass. And which plants do insects and diseases attack first? Answer: weakened plants, be they weakened by nature or mankind with the mower.

As for what the correct mowing height is, it depends on the grass.

For today, I’m sticking with the three most common species we grow in our lawns in this area: St. Augustine, centipede and common Bermuda. There are references that give mowing instructions for all the other grasses that will grow somewhere in Mississippi like zoysia, Bermuda hybrids, carpet grass and even Bahia intentionally grown as a lawn grass. Plus, there are the cool season overseeding of ryegrass or red fescue to give a wintertime green hue to lawns, especially those to the north where warm weather grasses don’t stay green as long as they do down here.

St. Augustine needs to be left fairly tall compared to the other two. Leave St. Augustine three inches high, never less than two and a half.

I’ve heard guys claim if they left it that tall they would have to mow more often. No, you won’t mow more often than cutting it lower. You’ll just be mowing taller grass than you’re used to. You’ll get used to it and nasty fungi with names like Rhizoctonia will be disappointed.

Two inches is a good height for centipede, no lower than an inch and a half. Centipede’s nickname is “Poor man’s grass” because if it likes your soil acidity and is not scalped at mowing, it will be happy, choke out weeds and look fine with minimal inputs of fertilizer, herbicides and other lawny stuff.

Common Bermuda is a dream come true for scalpers. It’s okay to drop down to a half-inch or up to an inch and a half with Bermuda. It has to have more sun and is not as pretty as the other two, but it will withstand the buzz cut.


Terry Rector writes for the Warren County Soil and Water Conservation District.