The 1/3 Rule: Mow Less Often for a Healthier Lawn

Cutting grass too short can stress your lawn, but following this simple guideline can reduce mowing by up to 35%.

Apr. 10, 2026 at 4:25pm

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An abstract, impressionistic scene of a vibrant green lawn captured in soft, hazy focus, conveying the serene beauty of a well-maintained outdoor space.Letting grass grow a bit longer between mowings helps keep lawns healthy and reduces the need for frequent cutting.Brooklyn Today

Lawn care experts recommend following the '1/3 rule' when mowing - never removing more than 1/3 of the grass blade height. This helps the lawn stay healthier, more disease-resistant, and reduces the need for frequent mowing. Cutting the grass too short can damage the plant's energy reserves and lead to more weeds. By letting the grass grow a bit longer between mowings, homeowners can save time and effort over the course of the growing season.

Why it matters

Maintaining a lush, green lawn requires a careful balance. Cutting the grass too short can weaken the plants, making them more susceptible to disease and weed growth. But following the 1/3 rule helps keep the lawn healthy and reduces the need for frequent mowing, saving homeowners time and effort.

The details

Lawn care experts recommend letting the grass grow to around 5 inches, then cutting it back to 3.5 inches, removing about 1/3 of the blade height. This is much longer than the typical 2-inch cut many homeowners prefer for a manicured look. But the longer grass is more disease-resistant, blocks out weeds better, and retains moisture in the soil. It also means mowing only every 8-9 days instead of every 5 days, saving 25-35% on mowing time over the course of the growing season.

  • For best results, let the grass grow to over 5 inches before mowing.
  • Cut the grass back to around 3.5 inches, removing about 1/3 of the blade height.

The players

Frank Rossi

Associate professor of horticulture at Cornell University's School of Integrative Plant Science, and a proponent of the 1/3 mowing rule.

Good Housekeeping Institute Home Improvement & Outdoor Lab

Conducts testing and research on lawn mowers and other outdoor equipment.

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What they’re saying

“Grass blades are like solar panels, absorbing energy from the sun and sending it down to the roots. When you cut off all that foliage, the grass is forced to live off its energy reserves, and a stressed-out lawn is not going to look very good.”

— Frank Rossi, Associate professor of horticulture

What’s next

Homeowners should measure their mower deck height and adjust it to the proper 3.5-inch setting to follow the 1/3 rule. They should also sharpen their mower blades regularly and consider using a mulching mower to return nutrient-rich clippings to the lawn.

The takeaway

By following the simple 1/3 mowing rule, homeowners can maintain a healthier, more resilient lawn that requires less frequent mowing, saving time and effort over the course of the growing season. This sustainable approach also reduces stress on the grass plants and promotes better weed and disease resistance.