Grow It Green: Late‑Summer Lawn Care Tips

When the September sun still feels warm but the evenings start to chill, it’s the perfect moment to give your lawn a little extra TLC before winter rolls in. In a recent chat on WMUR’s Grow It Green segment, meteorologist Jacqueline Thomas sat down with Kendall Kunelius of the UNH Cooperative Extension to walk homeowners through the do‑and‑don’ts of late‑summer lawn care.

First on the list: water wisely. The experts say it’s better to water deeply once or twice a week rather than a daily light sprinkle. A good rule of thumb is to aim for about an inch of moisture per watering, letting the soil soak down to the roots. If you notice the grass turning a muted gray or the soil feels dry a few inches below the surface, it’s time to turn the hose back on.

Next, trim back the mower height. During the heat of summer, most grasses thrive at a taller setting—around 3 inches—but as temperatures dip, cutting a half‑inch lower helps the grass collect more sunlight and prepares it for the cooler season. Just don’t make a dramatic chop; gradual adjustments keep the lawn from stress‑shocking.

Fertilizing is another key step, but the timing matters. A fall‑oriented fertilizer with a higher potassium content strengthens roots and boosts disease resistance. Kunelius cautions against using high‑nitrogen summer formulas now; they can encourage that unwanted, rapid growth you’ll struggle to manage once frost arrives.

Don’t overlook the soil itself. If your yard has felt compacted—common after a busy summer of foot traffic—consider a light aeration. Plug‑type aerators pull out small cores, letting air, water, and nutrients penetrate more easily. For lawns that look thin or have bare patches, overseeding after aeration can fill in the gaps, especially with a cool‑season grass mix suited to New Hampshire’s climate.

Leaves start to fall, and that’s not just a scenic moment; it’s a practical cue to keep the lawn clear. A thin layer of leaves can block sunlight and trap moisture, creating a perfect environment for fungal problems. If you have a manageable amount, a rake or leaf blower does the trick; for larger piles, a mulch mower can shred them into a nutrient‑rich blanket.

Lastly, give the lawn a quick health check. Look for weeds, thatch buildup, or signs of insect activity. A spot‑treat approach—using a targeted herbicide or an organic option—keeps the ecosystem balanced without a blanket chemical spray.

Following these straightforward steps—adjusted watering, smarter mowing, timely fertilizing, occasional aeration, overseeding, and diligent leaf removal—will set your lawn up for a healthy transition into fall and a vigorous start next spring. And as Jacqueline and Kendall remind us, a little effort now saves a lot of hassle later.