The Best Grass Seed for Pacific Northwest Lawns

lawn in front of a house in idaho

If you want a vibrant, green lawn, you need a grass type that can handle our rainy coastal areas and dry, sunny plains. The best grass seed for Pacific Northwest lawns is a mix of cool-season grasses like perennial ryegrass, fine fescue, Kentucky bluegrass, and tall fescue. 

Learn about the pros and cons of each grass type and how to choose the right one for your yard, whether you’re in the sun-blasted Eastern PNW or the mossy haven west of the Cascade Mountains.

If you want to dig deeper and find the best grass seed for your specific state, check out these articles:

Perennial ryegrass: Best grass seed for full sun 

perennial ryegrass in a lawn
Aaron J. Patton, Ph.D. | Purdue’s Turfgrass Science Program

Perennial ryegrass is very popular among homeowners on both sides of the Cascades. This grass will sprout in just four to seven days under full sun and well-drained, fertile soils. Plus, it’s highly resistant to wear and tear, so it’s perfect for yards that see a lot of foot traffic. 

However, when temperatures dip into the 20s for more than a few days, ryegrass struggles to survive — and without some winter prep, it might even die. (Learn how to avoid this in our guide, “Perennial Ryegrass: How to Grow and Care for It.”)

So, what’s the best approach? Get a seed mix of perennial ryegrass with a bit of fine fescue, such as hard fescue or chewings fescue. Fine fescues are more cold-tolerant than most other cool-season grasses for the PNW, except bentgrass. 

The exact mix ratio always depends on your lawn’s specific needs. Michael Neff, professor in the Department of Crop and Soil Sciences at Washington State University, explains that a higher percentage of perennial ryegrass will give your lawn a coarser texture but will need more water and fertilizer. Fine fescue has a finer, denser look and requires less maintenance, but it doesn’t handle heavy foot traffic as well. The key is finding the right balance for your lawn.

If you have areas that get partial shade, increase the fine fescue ratio or include a tough fine fescue cultivar. Neff recommends strong-creeping red fescue because it has underground stems called rhizomes that help it regrow after damage, whether from foot traffic in busy spots or drought stress.

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Fine fescues: Best grass seed for full shade

fine fescue grass
Aaron Patton | Purdue’s Turfgrass Science Program

If your yard is shaded by trees or nearby buildings, try fine fescue. Varieties like creeping red fescue, hard fescue, and chewings fescue are the most shade-tolerant of Northwest-adapted grasses. Their deep root system allows them to extract moisture and nutrients from the soil surface, even in those spots in your yard that get sunshine once in a blue moon. 

Now, while fine fescues are generally hardy, they aren’t a fan of Western PNW’s soggy conditions. They can struggle with grass fungus and other lawn diseases. (Learn more in our guide: “Most Common Diseases in Fine Fescue Grass.”)

To combat this, turf grass specialist Alec Kowalewski from Oregon State University recommends blending fine fescues with a small amount of perennial ryegrass. This way, you’ll enjoy the best of both worlds: the excellent shade tolerance and soft, velvety texture of fine fescue, and the quick establishment and resilience of ryegrass. 

For lawns in the drier Eastern PNW, focus on mixes that include sheep fescue and hard fescue, which are the most drought-tolerant fine fescue varieties. 

Pro tip: If you live in the western side of the Pacific Northwest, your soil is likely acidic (i.e., with pH levels between 5.0 and 6.5). This happens because of the heavy rainfall and clay. Fine fescues and perennial ryegrass can handle mildly acidic soils, but you might need to add lime to help them grow better and get the nutrients they need. If you’re not sure when or how to do it, check out our article, “When to Apply Lime to Your Lawn in the Pacific Northwest.”

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Tall fescue: Best grass seed for coastal lawns in Western PNW

tall fescue
Aaron Patton | Purdue’s Turfgrass Science Program

Tall fescue is perfect if you live by the ocean and your lawn gets beat up by salty air and strong winds. This grass can handle the salt way better than other grasses. Plus, it has good drought tolerance, which is important in coastal areas where strong winds can quickly dry out the soil.

The downside is that tall fescue struggles to survive during Western PNW’s cold snaps, especially in areas that don’t get consistent snow cover to insulate it from the freezing temperatures (e.g., the Willamette Valley or along the Oregon Coast).

Neff explains, “Tall fescue has extremely deep roots that can reach groundwater, but they don’t go dormant. When tall fescue is brown, it’s likely dead.” 

Fine fescue is a hardier alternative. Neff points out that both fine fescues and perennial ryegrass do well in salty conditions, with fine fescue also being able to go dormant when water is scarce and recover when it’s available again. Creeping bentgrass is another popular option for cold hardiness. However, he cautions, “I would stay away from creeping bentgrass except for golf course uses. It can become weedy in other lawns and requires unique cultural and mowing practices.”

To make your lawn resilient year-round, try a blend of tall and fine fescue. You can also overseed with perennial ryegrass in the fall to suppress weeds and get a quick green-up in the spring. Not sure how to do it? Read our guide on “How to Overseed a Lawn” for all the tips and tricks you need.

Note: If you’re looking for the best grass types for your specific area, we have guides covering some of the major cities and regions in the Western PNW, including:

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Kentucky Bluegrass: Best for drought-tolerant lawns in Eastern PNW

closeup of kentucky grass in a lawn
Shutterstock

If you’re tired of spending your summer weekends trying to revive your parched, patchy lawn, Kentucky bluegrass is your best bet. It turns brown to conserve moisture but quickly greens up again with a little rain or irrigation. In addition, it can self-repair by spreading its underground rhizomes. This helps fill in bare spots and keeps your lawn looking thick and healthy throughout the growing season.

Kentucky bluegrass prefers well-drained, loamy soils with pH levels between 6.0 and 7.5, but it can still thrive in Eastern PNW’s alkaline soils. Just keep an eye on the pH —if it goes above 7.5, you might see some yellowing due to nutrient deficiencies, especially iron.

Neff explains, “Turfgrasses generally grow better in slightly acidic soils than alkaline soils. For very alkaline soils, the best first step is to do a soil test and then find a local reputable turf management company for treatment with an acidifying fertilizer or other approaches they recommend.” 

If you find out that your soil is too alkaline, check out our guides on adjusting soil pH and soil testing to get your lawn back on track.

Note: While Kentucky bluegrass is the best choice, you might also want to think about tall fescue and fine fescues. Neff points out that these grasses don’t mix well together because of their different leaf textures. However, either type can be combined with Kentucky bluegrass. When you blend them, Kentucky bluegrass keeps its rich, emerald color and fine texture, while the fescues add extra resilience and drought tolerance.

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FAQ about grass seed for Pacific Northwest lawns

What is the best grass seed for overseeding in Pacific Northwest?

The best grass seed for overseeding in the Pacific Northwest depends on your specific lawn’s conditions, such as sunlight, shade, and moisture levels. As a rule of thumb, overseeding a mix of fine fescue and perennial ryegrass works best for our climate. 

You can also add colonial bentgrass to your overseeding mix if you have areas with a lot of foot traffic, like play areas or near paths. This grass grows thick and tough, but it needs regular upkeep. (Learn how to maintain it in our guide, “How to Care for a Bentgrass Lawn.”)

If you’re in eastern Idaho and struggle to keep your lawn green during the hot, dry summers, consider overseeding with buffalograss. You can blend it with fine fescue and perennial ryegrass to grow a yard that looks great in both sunny and partially shaded spots while also being more drought-resistant.

What should I consider when buying grass seed for the Pacific Northwest?

To choose the right grass seed for your yard, think about the soil type in your area and how you plan to use the grass.

Neff advises, “Don’t just buy a bag of seed. It is important to know what you want to use the turf for (utility, ornamental, sports) and where it will be grown (soil type, pH, sunlight). Check the types of seeds in the blend and make sure these are the species that you want for your purpose.” 

He adds, “Also, remember that there are different varieties for each of these species that have been bred/adapted for particular uses, areas and environments. The best way to learn about adaptability of varieties is to go to the National Turfgrass Evaluation Program (NTEP) website.”

When should I plant grass seed in the Pacific Northwest?

According to Neff, “The fall is best as there will be less weed pressure and more moisture as the seeds germinate and establish.” Aim to plant grass seed between Sept. 1 and Oct. 15 for the best results. If you miss that window, you can also plant from Feb. 15 to May 1

However, keep in mind that spring planting in the PNW, especially on the west side, requires a bit more care. Moss and fungus love our cool, damp weather, so you’ll need to watch out for them. Check our article, “Common Pacific Northwest Lawn Problems to Watch Out For.” for more info on these issues. 

Are there any native grasses that work well for lawns in the Pacific Northwest?

Yes. Some Pacific Northwest native grasses you can try are Idaho fescue, bluebunch wheatgrass, and tufted hairgrass. 

“Tufted hairgrass can be used for lawns that do not get a lot of wear/abuse,” Neff said. “It is shade tolerant and thrives on very low pH (acidic) soils. It should do well on both sides of the state.”  

He has a breeding program focused on improving this grass for lawn use and potentially replacing artificial turf, with active trials in Pullman and soon in Mount Vernon. If in doubt, you can check them out to see how tufted hairgrass performs before making the switch. 

Are there alternatives to traditional grass for lawns in the Pacific Northwest?

Yes. David K. McDonald, author of the Seattle Public Utilities report on “Ecologically Sound Lawn Care for the Pacific Northwest,” recommends planting clover, creeping thyme, or moss — depending on your lawn’s sunlight and moisture levels. Read our article, “The Best Lawn Alternatives for the Pacific Northwest” for more tips on choosing the right option for your yard.

When to Call in the Pros

The Pacific Northwest’s weather can be unpredictable, making it tricky to pick the right grass seed or mix for your lawn. To make things worse, each grass variety has its own unique needs, and keeping up with them can take a lot of time. Hiring a local pro in your area takes the stress away and ensures your turf thrives beautifully. Use LawnLove to connect with reliable experts across the Pacific Northwest, including Seattle, Spokane, Portland, Nampa, and more.

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Main Image Credit: John Johnson House (Caldwell, Idaho) | Tamanoeconomico | Wikimedia Commons | CC BY-SA 4.0

Tatiana Barrie

Tatiana Barrie is a seasoned writer and outdoor enthusiast, passionate about keeping green spaces thriving. When not writing, she enjoys tending to her own yard and exploring new gardening practices