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How to Manage Pests

The UC Guide to Healthy Lawns

Cutting off one-third of the grass blade

No more than one-third of the grass blades should be cut at a time. Cutting off one-third of the blade at a time removes just enough to keep your lawn healthy and not too much to stunt the growth.

What happens if you cut more?

If you neglect your lawn for a few weeks during its active growth period and it gets too high, you will impair the root growth if you cut more than one-third of the blade to reach the recommended height. Growth will slow as the grass puts its resources into the leaf tips to help them recover. Also, repeatedly cutting too much or mowing too short will leave your lawn susceptible to weed invasions, diseases, and an overall thin stand. It can also result in an excess of thatch developing.

For instances where the grass has grown too tall (vacations, mower mechanical problems, prolonged rainy periods), it is advisable to mow the lawn more frequently than usual until the lawn reaches the desired height. Never take off more than one-third of the blade at a time.

How much of the lawn shown below should be cut?

Illustration of a button1 inch Illustration of a button1.5 inches

Illustration of a lawn mower that will mow at 1 or 1.5 inches depeding on user's choice

Statewide IPM Program, Agriculture and Natural Resources, University of California
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Agriculture and Natural Resources, University of California

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