COLUMBIA, Mo. – Winter is finally releasing its grip, so lawns will be greening up and growing. It will soon be time for one of the most basic homeowner rituals: mowing the lawn.

Getting ready for lawn-mowing season means more than just filling the mower with fuel and starting it up. To keep your lawn in good shape, your mower needs to be ready and you need to get a head start on controlling weeds.

“Check the (mower) air filter to make sure it’s not plugged up. You may want to change the spark plug,” said Brad Fresenburg, assistant professor of plant sciences for University of Missouri Extension. “More importantly, make sure that mower blade is sharp, and you’ll need to check that on a regular basis throughout the summer.”

Mower tuneup is important, but this is also the time for preventing crabgrass.

“Folks should consider whether they want to add a pre-emergence herbicide for crabgrass prevention. Time for application is right around the corner  as long as we continue to see warmer temperatures,” Fresenburg said.

Don’t make the mistake of confusing crabgrass prevention with applying “weed and feed” products.

Many people assume that a “weed and feed” will control all weeds, but that’s not necessarily the case. “The ‘weed and feed’ products control broadleaf weeds, like dandelions,” Fresenburg said. “The crabgrass preventers are targeted toward annual grasses, like crabgrass.”

Some of the crabgrass preventers will also control a few of our annual broadleaf weeds, Fresenburg said, so they tend to be more inclusive than the “weed and feed” products. Effectiveness and control vary from product to product, so it’s essential that homeowners read the labels.

Once mowing season is in full swing, proper mowing practices can mean the difference between a healthy, vibrant lawn and one choked by weeds and plagued by thinning patches.

The best mowing height for tall fescue lawns is 3-4 inches, Fresenburg said. “The reason is we get an excellent shade effect, which prevents weed seed from germinating. If we mow tall, we can reduce annual weed populations by 80 percent.”

Mowing tall also improves the health of your lawn.

“It will cause your grass to develop a deeper root system. So when we get into the warmer, droughtier parts of the summer, your grass can draw moisture and nutrients from deeper in the soil, giving you better heat and drought resistance,” Fresenburg said.

The best practice for a healthy lawn is mow tall and let the clippings fall.

“We know we can return some nutrients by this practice,” Fresenburg said. “The clippings will filter through the turf canopy and decompose fairly rapidly. This practice will add up to 50 percent potassium and up to 30 percent annual nitrogen to the soil.”

To get even distribution of the grass clippings, avoid mowing the lawn when it’s wet. Wet grass tends to clump together, and this can cause thin patches in your lawn, Fresenburg said.

Do you mow your lawn in the same pattern week after week?

“You should change the mowing direction on a regular basis so you don’t burn a particular mowing pattern in your lawn. I know everyone thinks they have the best and most efficient way to mow their lawn to get it done in the shortest amount of time,” Fresenburg said. “If you change the mowing pattern, maybe north-south, east-west or some diagonal patterns on a regular basis, it will make your lawn look better.”

For more information, see the following MU Extension publications:

• “Cool-Season Grasses: Lawn Maintenance Calendar” (G6705)
• “Don’t Bag It Lawn Care” (G6959)

Writer: Debbie Johnson