Minnesota lawns face unique challenges during late summer. The combination of heat, sporadic rainfall, and seasonal pests can wreak havoc on even the most carefully tended yards.
Many homeowners unintentionally damage their lawns through common maintenance mistakes that could easily be avoided with the right knowledge.
1. Mowing Too Short
Scalping your lawn might seem like a time-saver, but short grass struggles in Minnesota’s late summer heat. When grass is cut below 3 inches, it develops shallow roots and becomes more vulnerable to drought stress.
Taller grass shades soil, keeping it cooler and reducing water evaporation. For August and September, set your mower height to 3-3.5 inches and your lawn will thank you with deeper roots and better drought resistance.
2. Watering At The Wrong Time
Sprinklers running at high noon waste precious water and can actually harm your lawn. The midday sun evaporates much of the moisture before it reaches the roots, and water droplets on grass blades can act like tiny magnifying glasses, scorching the grass.
Early morning watering (5-9 AM) gives your lawn time to absorb moisture before the day heats up. Deep, infrequent watering encourages stronger root growth than daily light sprinkling.
3. Ignoring Grub Damage
Those mysterious brown patches appearing in August might not be drought—they could be grubs! These C-shaped beetle larvae feast on grassroots just below the surface, causing sections of lawn to die off quickly.
Look for turf that pulls up easily like a loose carpet, revealing white grubs underneath. Beneficial nematodes or milky spore are natural solutions that won’t harm beneficial insects, while chemical treatments work faster for severe infestations.
4. Over-fertilizing In Heat
Dumping fertilizer on your lawn during hot August days can burn grass faster than you’d imagine. The nitrogen that normally feeds your lawn becomes toxic in high temperatures, turning lush green turf into crispy brown patches within days.
Minnesota lawns need minimal fertilizer during late summer stress periods. Save your major feeding for early fall when cooler temperatures return. If you must fertilize, choose a slow-release formula and apply at half-strength.
5. Neglecting Weed Control
Late summer weeds like crabgrass and dandelions aren’t just eyesores—they’re stealing water and nutrients from your grass during the season’s most stressful time. Many homeowners give up weed control by August, allowing these invaders to establish and set seeds.
Spot-treating problem areas with targeted herbicides prevents weeds from taking over. For organic options, vinegar-based solutions work well on hot, sunny days. Remember to always apply when rain isn’t expected for 24 hours.
6. Compacting Soil With Heavy Traffic
Summer barbecues and backyard games are Minnesota traditions, but concentrated foot traffic creates compacted soil that suffocates grass roots. Areas where people frequently walk or gather become hard-packed, preventing water, air, and nutrients from reaching the roots.
Aerating these compacted zones allows your lawn to breathe again. Consider creating designated pathways with stepping stones or mulch to direct traffic away from vulnerable turf. Your grass needs room to grow, especially during stressful late summer conditions.
7. Letting Thatch Build Up
A spongy feeling underfoot might seem like healthy turf, but excessive thatch—that layer of dead grass between soil and living blades—can suffocate your lawn. When thatch exceeds ½ inch thick, it blocks water and nutrients while harboring pests and diseases.
Late summer is perfect for dethatching Minnesota lawns before fall recovery begins. Rent a power rake or use a dethatching rake for smaller areas. Follow up with overseeding to fill in thin spots and strengthen your lawn for the coming winter.
8. Skipping Fall Overseeding Prep
Many Minnesota homeowners miss the late summer window for lawn renovation, waiting until it’s too late. August and early September are actually prime times to prepare for overseeding, while soil temperatures remain warm enough for seed germination.
Thinning areas need fresh seed before fall, not after. Start by mowing lower than usual (but not scalping), then lightly rake soil to create good seed-to-soil contact. Choose Minnesota-adapted grass varieties like Kentucky bluegrass mixed with perennial ryegrass for best results.
9. Forgetting About pH Balance
Minnesota’s native soils tend toward acidity, which worsens over time with rainfall and fertilizer use. By late summer, unbalanced soil pH can lock up nutrients, making them unavailable to grass even if you’re fertilizing regularly.
Testing soil pH now gives you time to correct imbalances before fall. Most Minnesota lawns thrive with a pH between 6.0-7.0. Lime applications help neutralize acidic soil, while sulfur lowers pH in the rare case of alkaline conditions. Proper pH means healthier grass with fewer inputs.
10. Using Blunt Mower Blades
Dull mower blades tear grass instead of cutting it cleanly, leaving ragged edges that turn brown and increase water loss. These wounds also create entry points for diseases that thrive in late summer conditions.
Sharpen your mower blade at least twice per season—once in spring and again mid-summer. A freshly sharpened blade makes a clean cut that heals quickly and maintains grass health. You’ll notice the difference immediately in how your lawn looks after mowing.