By Kym Pokorny, OSU Extension
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.
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.”
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.
- 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.
- 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.