CORVALLIS, Ore. — Lawns often languish in the summer heat without regular watering — but that doesn’t mean the grass is dead.
Once fall rains return, grass typically greens up quickly, said Alec Kowalewski, Oregon State University professor and Grover Family Endowed Sustainable Urban Landscapes Specialist.
“You should always try renovation before putting in a new lawn because it’s difficult to get a stand of grass established. If you have something to begin with, go with renovating.”
Letting your lawn go dormant over the summer can be a good water-saving practice. However, lack of irrigation can open the door for weeds to establish. Plus, foot traffic and use throughout the summer can compact the soil, leading to brown or bare spots.
Luckily, fall is an excellent time to rejuvenate your lawn — and in most cases, a full replacement isn’t necessary.
“You should always try renovation before putting in a new lawn because it’s difficult to get a stand of grass established,” Kowalewski said. “If you have something to begin with, go with renovating.”
Lawn needs can vary widely — from a few patchy areas to extensive weed takeover or hard, compacted soil. In most cases, a regular renovation is enough. Once you’ve restored your lawn, follow three essential steps to keep it healthy and better able to outcompete weeds:
- Water
- Fertilize
- Mow properly
Watering wisely
Water about 1 inch per week, but don’t apply it all at once.
“If you look at the roots, the majority are in the top 1 inch of soil,” Kowalewski said. “The deeper you go, the fewer roots there are, so watering more than a quarter inch at a time is a waste.”
Apply smaller amounts more frequently when it’s not raining.
Fertilize on holidays
Fertilize four times a year. An easy way to remember:
- Memorial Day
- Fourth of July
- Labor Day
- Thanksgiving
Mow with purpose
Never remove more than one-third of the grass height at a time. If your lawn is 3 inches tall, mow only 1 inch. Removing too much weakens the grass and makes it more vulnerable to weeds and disease.
Most homeowners prefer grass heights around 2 inches, but taller is even better.
“Increase the height of the grass as tall as you can stand it and mow once a week,” Kowalewski said. “If you mow it to an inch, it’s horrible for the plant — you’re reducing root depth and stress tolerance. And you’ll have to water more.”
- Mow weekly in spring and fall
- Mow less frequently in summer and winter
- Leave clippings unless they form clumps — they decompose quickly and return nitrogen to the soil
Steps for renovating a lawn
Regular renovation
- Test soil pH
- Use OSU Extension’s Guide to Collecting Soil Samples for Farms and Gardens or purchase a test kit from a nursery. Lawns thrive in a pH of 6.0 to 6.5.
- Remove weeds
- Pull by hand or apply a broad-spectrum herbicide.
- Aerate the lawn
- Use a mechanical aerator (available at rental centers). Focus on bare or compacted spots. Rake away the soil plugs that the machine removes.
- Apply lime if needed
- If the pH is below 6.0, add lime. In Western Oregon, most lawns benefit from liming every two to three years.
- Fertilize
- Choose a product high in nitrogen (N), with low or no phosphorus (P) and a medium level of potassium (K). For example, use a fertilizer labeled 20-2-6. Apply with a rotary spreader.
- Overseed
- Apply grass seed at the recommended rate, using a drop seeder for even distribution. Increase the seeding rate in bare spots.
- Water daily
- Unless it rains, water lightly each day to keep the soil moist until seeds germinate.
Major renovation
Complete the regular renovation steps above, plus:
- Mow short before starting
- Cut the grass as low as possible before renovation.
- Dethatch the lawn
- Rent a dethatching machine or power rake. Run it across the lawn twice in opposite directions to expose as much soil as possible. Remove loosened thatch before changing directions.
- Add a mulch layer
- After seeding, apply a thin layer (no more than ¼ inch) of sawdust, bark dust or compost to help with germination. Don’t overdo it — too much can hinder seedling emergence.
- Use a roller for even seed-to-soil contact
- A wire drum roller can help press seed and mulch into the soil for better results.
More resources
- Watch the video: Integrated Pest Management for Turfgrass
- Explore OSU Extension publications:
Previously titled Now’s the time to spiff up ragged lawns
