TUESDAY, APRIL 15, 2025
How to grow and maintain a healthy lawn
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Weston Miller
March 2022
A healthy lawn resists invasion by moss, weeds, insects and diseases. If your lawn is not meeting your expectations, consider a lawn renovation.
Maintain the right growing conditions needed for strong, healthy turfgrasses.
Lawns change over time. After sowing lawn seed or laying sod, the mixture of desired turfgrasses and broadleaf weeds, grassy weeds and moss will evolve.
Soil drainage, soil fertility, sunlight, water stress, and how the lawn is cared for and used influence how a lawn looks over time.
Set realistic expectations. Match the lawn standards you want to maintain with the right maintenance schedule.
These tips are mainly developed for the Willamette Valley. For lawn care in central Oregon, visit turfgrass maintenance calendar for central Oregon.
Consider a no-till lawn renovation
Consider a total lawn renovation if moss, weeds, insects or diseases are overwhelming your lawn.
Late summer is the best time of year for a lawn renovation.
Photo at top shows two renovation techniques:
Complete renovation (left): Herbicide dethatch and reseed.
Partial renovation (right): Dethatch and reseed.
Both treatment areas in the photo are ready for seeding.
See Practical Lawn Establishment and Renovation.
Grow a healthy lawn
A healthy lawn resists invasion by moss, weeds, insects and diseases.
Plant grass species best suited for your area.
Plant disease-resistant cultivars or mixtures.
Lawn grasses require full sun to thrive. Lawns grown in shady areas will require more care to maintain to high standards. Or tolerate moss, which will likely grow in shady areas.
Apply fertilizer and water to grow a lawn that matches the lawn standards you wish to maintain.
Regular mowing
Mow regularly. For most lawns, a mowing height of 2–3 inches is recommended.
Keep your lawnmower blades sharp.
Mow weekly during most of the growing season.
Mow twice per week when the grass is growing quickly during mid- to late-spring.
Cut only one-third of grass height at each mowing.
Make at least two passes over your entire lawn. Go at a 45- or 90-degree angle to your first pass to avoid ruts and compaction from the mower.
Use a mulching mower (has a special blade and enclosed deck) or reel mower to chop up debris into small pieces.
Mulch-mowing recycles nutrients to the lawn.
Rake up excess lawn clippings that don’t get finely chopped.
If you don’t use a mulching mower, bag and remove the lawn clippings.
Mow higher in periods of stress such as dry or hot weather. The longer leaves promote root growth to absorb water from the soil.
Apply grass seed in spring or fall
The grasses in lawns naturally thin out over time. Keep your stand of grass thick and robust by applying grass seed regularly.
Apply grass seed or lawn patch to thin areas in the spring and late summer/early fall. Cover up bare soil with grasses.
Apply grass seed over your entire lawn at least every two years before it thins out.
Fertilize, but not too much
Unfertilized lawns tend to be thin and light green or brown in color. They often have moss and weeds mixed with grasses.
Unfertilized and overfertilized lawns are both prone to pests and disease.
Lawns grow vigorously when enough nutrients are available, especially nitrogen.
For low-maintenance lawns, apply fertilizer once in the fall to promote robust growth the following spring. Apply fertilizer in late spring and summer too for higher-maintenance lawns.
Mulch-mowing provides some nitrogen for your lawn. It is less work than mowing and bagging the clippings.
See Fertilizing Lawns for more details.
Check soil pH and amend as needed
Lawns grow best with soil pH between 6.0 and 6.5.
Check your lawn’s soil pH. Amend as needed.
We recommend sending soil samples to laboratories for analysis. Professional soil tests are more accurate than do-it-yourself options. Ask your soil testing lab to interpret the results and provide recommendations for amending soil pH.
For more information about soil pH testing, see:
A Guide to Collecting Soil Samples for Farms and Gardens.
Analytical Laboratories Serving Oregon.
How do I test my garden soil?.
Video: How to collect a soil sample.
Lawn watering decision-making
Lawns can survive the summer without irrigation by going dormant and turning brown. Unirrigated lawns often have moss and weeds mixed with grasses. They don’t stand up to heavy wear.
Watering is required if you want your lawn to look green through the summer. Plan to water from mid-May to early September. Some locations or dry years might require irrigating earlier or later than these dates.
A buried irrigation system with pop-up sprinklers and a timer is the best method to irrigate high-maintenance lawns. Learn to use your irrigation controller for the best results.
Lawn watering tips
Use several range gauges or empty, shallow food cans (such as tuna) placed on your lawn to measure how much water you apply.
Don’t apply more than one-half inch of water at a time.
Plan to water three or four times per week. Each watering should be between one-quarter and one-half inch.
Adjust the amount of water you provide each week through the season. Determine a baseline. Add more when the weather is hot and dry. Water less when it is cooler.
Use a screwdriver as a soil moisture gauge to determine if you are watering enough or too much. Push the screwdriver into the lawn surface.
If it easily penetrates to the handle, ease back on watering.
If the ground is hard and it is difficult to insert the screwdriver, water more.
Perform routine maintenance on sprinkler heads.
Water in the morning, so grass can dry quickly.
Provide good soil drainage.
Aerating
Aerate your lawn if the soil is compacted or water does not penetrate well. Aerating helps air to penetrate the soil. Aerated soil helps grow healthy lawn grasses.
Yard equipment rental stores rent power aerating machines. Hand tools are available, but not as effective as the power tools.
Dethatching
Thatch is built-up organic material at the base of grass plants. When it builds up, grasses die back and weeds and insect and disease pests might occur.
Remove thatch if it exceeds one-half inch deep.
Apply grass seed to your lawn after aerating and/or dethatching.
See Thatch in Home Lawns for more information.
The photo to the right shows a power dethatching machine. They remove thatch on the lawn surface. This material needs to be raked up and removed.
Yard equipment rental stores rent power dethatching machines. Hand tools are available, but not as effective as the power tools.
Consider an artificial lawn
If all of this work to maintain your lawn seems overwhelming, consider installing artificial turf. It looks good year-round and requires minimal care.
Artificial turf may contribute toward micro-plastic pollution in the environment.
Posted 1:12 PM