Mow Like a Pro: Six Tips for Greener Lawns and Cleaner Water

Let’s face it: not all of us can have yards covered in glorious native perennials. Most of us have plain old turf-grass lawns to maintain. And with summer approaching, it’s time to dust off the lawn mower and settle in for another season of sweaty yard-care fun.

But don’t go firing up the mower just yet. First, you should know that what you’re doing in your yard could be sending pollution into nearby waterbodies. Follow these six tips to keep your yard green without impacting the water quality of our rivers, lakes and streams.

1. Mow High

A tape measure is used to check the height on a lawn mower.
Setting your mower to a height of three inches or greater will produce denser, healthier turfgrass and help block weeds.

Shorter is not better when it comes to lawn care. In fact, cutting your grass at a height of three inches or higher will produce a denser, healthier root system. This will make your grass more resistant to weeds, drought and erosion. Longer grass also helps trap potential pollutants that would otherwise blow into stormdrains. 

Remember: Grass is like any other plant; it needs sunlight to grow. The longer its leaves, the more sunlight it can capture. Take a ruler or tape measure and check how high your mower is set from the ground. If it’s less than three inches, adjust it accordingly.

2. Cut One-Third (or Less) at a Time

Close-up of a lawn mower cutting grass.
If you want to keep your lawn healthy and prevent pollution, don’t cut more than one-third of the grass length at a time.

We all know that feeling of coming home to a lawn that looks like a jungle and realizing it’s been more than a week since we last mowed. Time to make up for lost time and cut it extra short, right?

Wrong. Cutting off more than a third of the grass blade at one time stresses your turfgrass. It also leaves your yard littered with clumps of grass clippings that are too big to blend back into the lawn. In addition to smothering the live grass underneath them, these clippings can end up in stormdrains, sending phosphorus, nitrogen and other excess nutrients to the nearest available waterbody.

Don’t cut off more than one-third of the height of your grass when you mow. Instead, consider cutting more frequently, especially during spring — when grass grows more quickly than it does in the summer.

3. Keep Your Mower Blades Sharp

A lawn mower blade.
Check your mower blade frequently to see whether it needs sharpening.

If the tips of your grass have a yellowish or whitish appearance after you mow, your lawn mower blade might be dull. A dull blade can damage the grass and cause your mower to run less efficiently. Most hardware stores offer blade-sharpening services for a small fee.

4. Leave the Clippings on Your Lawn

Grass clippings flying from a push-reel lawn mower.
Grass clippings contain the same amount of nutrients as a round of fertilizer — which is good if they stay on your lawn, but bad if they enter the stormdrains.

Grass clippings provide vital nutrients to your lawn; in fact, grass clippings provide the equivalent of one round of fertilizer every single time you cut your grass. The same goes for mulched leaves (although if the leaves cover more than 50 percent of your lawn, you may want to bag them up or compost them instead).

More importantly, when you blow grass clippings into the street, they get washed into stormdrains and carried out into your local waterways. It’s essentially like dumping fertilizer directly into the Mississippi River. Leave your grass clippings on your lawn, and sweep them out of the streets so they don’t end up in stormdrains.

5. Water Wisely

Using a hose to water a turfgrass lawn.
Your lawn might not need as much water as you think. The equivalent of one inch per week of rain should be sufficient to keep it green.

If you choose to water your lawn to help keep it green, water it in the early morning so that the grass retains the moisture better. Lawns generally require about one inch of water per week, so use a rain gauge to determine how much (if any) extra watering you really need. Also, avoid sprinkling on hard surfaces so that you aren’t needlessly wasting water and washing pollution into nearby stormdrains.

If a lush, green lawn is not of critical importance to you, then try not to water more than necessary. If your lawn starts turning yellow or brown in the mid-summer heat, don’t panic. It might look like it’s dying, but it’s only going dormant. It will green up again in the fall, or after the first good rain.

6. Fertilize Smart

A woman reads instructions on a bag of fertilizer
When shopping for fertilizer, look for products that advertise zero phosphorus, and avoid weed-and-feed combinations.

If you choose to use fertilizer, do it in the fall when it will be most effective. Only use zero-phosphorus fertilizers, and apply the amount directed by the manufacturer. Also, avoid combination weed-and-feed products, which might not be effective for your specific conditions. Instead, consider having the University of Minnesota run a test on the soils in your yard. It’s inexpensive, and you’ll get great information on the right kind of fertilizer combination for your yard.

Sweep up any excess fertilizer that falls on hard surfaces. Finally, as an alternative to fertilizer, consider aerating your lawn in the fall; it will strengthen your lawn naturally.

Bonus Tip: Watch Our How-To Videos

If you really want to get in depth on preventing pollution at home, the MWMO’s YouTube channel features a series of videos on best practices for lawn care, covering everything from lawn care basics to weed control. Check out the playlist below:


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