For a green lawn, mow high and delay watering or fertilizing


A few simple practices will help ensure that your lawn endures the extremes of the summer season.

A few simple practices will help ensure that your lawn endures the extremes of the summer season.

Johnson County Expansion

Spring so far has been a roller coaster of ups and downs. Late spring frosts and record highs, all in a matter of weeks. As summer approaches, will this ride continue? Will it be hot and dry, or cool and humid? We never know until it happens.

No matter what the impending weather conditions are, these simple practices will help ensure our lawns have a better chance of surviving the ride and enduring the extremes.

Mow high and let stand

Proper mowing height is the most important cultural practice for good lawn care. Summer mowing heights should be high, 3 to 3½ inches for cool season bluegrass and tall fescue lawns. However, Zoysia, a warm season grass, can be mowed lower.

Higher mowing heights provide several benefits. The longer green blades shade the ground, which keeps the lawn cooler and reduces evaporation. The extra growth provides more green area for food making.

With higher mowing heights, the stresses of summer are reduced, as is the amount of water needed to keep grass green longer. Checking your mowing height is easy. Mow a strip and use a ruler to measure the height of the blade. Don’t always rely on trimmer settings as they are often not marked in inches. Use the mulch cap and setting on your mower and let the waste recycle back into the lawn. The clippings return nutrients to the soil bed and naturally nourish the lawn.

Delay watering

The longer we can delay additional watering, the more drought tolerant your lawn will be. Normally, natural rainfall is sufficient to keep the lawn in good growing condition until late June or even early July. Letting the lawn get stressed causes the grass to develop stronger, deeper roots. Keeping the soil moist in spring and early summer with frequent watering promotes shallow rooting. Shallow roots are more susceptible to heat stress.

Lawn irrigation systems can be maintained and prepared for summer, but until the heat and drought sets in, turn off the timer. If it gets dry, turn on the timer and soak the lawn deeply with about an inch of water. Unless your lawn is showing signs of stress and there is no rain in the forecast, keep the lawn water lean. Not only does this harden the lawn, but it also saves money and resources.

Go lean on the fertilizer

Summer is stressful and lawns can be more demanding. Grass tries to survive, not thrive, during the scorching days of summer and additional fertilizers are not needed at this time. Research has shown that using summer fertilizer on bluegrass and tall fescue can increase water requirement and decrease heat tolerance by increasing internal processes. This forces the lawn to extra growth when it wants to survive.

A leaner nourished lawn stands up to summer stress. Delay fertilizing cool season lawns until the cooler days of fall arrive. An application in early September is the most important and effective time to feed the lawn and will help overcome summer damage and stress.

For now, buckle up and see how wild our summer roller coaster ride will be. It always pays to prepare for the worst and hope for the best when it comes to maintaining your lawn in the summer.

Dennis Patton is a horticultural research and extension officer at Kansas State University. Have a question for him or other academic extension experts? Email them to [email protected]

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