A PACIFIC NORTHWEST EXTENSION PUBLICATION • PNW299
Washington State University • Oregon State University • University of Idaho
Introduction
Scientists at Washington State University, Oregon State University, and the University of Idaho have conducted turfgrass variety evaluation trials in the Pacific Northwest for over 50 years, and continue to cooperate in local, regional, and national testing programs to provide current information on the performance of most turfgrass species marketed today. Data from these trials are used as the basis for recommendations to establish turfgrass under common and complex field situations. The National Turfgrass Evaluation Program (NTEP) lists all the data collected from around the country at www.ntep.org. For best results, use data from the research site closest to your turfgrass management location.
The blends, mixtures, and rates in this publication are current recommendations for homeowners, seed companies, salespersons, and turfgrass managers based in Washington, Oregon, and Idaho. No variety names are included because of the variability of adaptation for specific regions of the Pacific Northwest and the constant changes as to which cultivars may be available to turfgrass managers. If you have questions about particular varieties, contact your local Extension personnel or go to the website of the nearest turfgrass program.
Turfgrass Seed Characteristics
Seeds per pound.Turfgrass seeds are different sizes. The number of seeds per pound varies widely among grass genera, species, and even varieties. Seed size influences the seeding rate required to produce comparable stands; for example, bentgrass is seeded at a lower seeding rate than tall fescue. Table 1 compares the seed size of most common Pacific Northwest turfgrasses.
Germination and purity. Germination of a seed lot refers to the amount of pure seed that is viable, or the percentage of seed that will germinate under ideal laboratory conditions. Purity is the freedom from matter other than the seed itself. Germination and purity are expressed as a percentage of the total seed in a particular lot. The germination and purity percentage can vary and still meet state certification standards and federal seed laws.
Pure live seed (PLS) is the percentage of seed from a particular variety that will germinate and produce viable seedlings. PLS is calculated by multiplying the percent germination by the percent purity. For example, if 80% of Lot No. 1 germinates and is 85% pure, while 82% of Lot No. 2 germinates and is 98% pure, the PLS of Lot No. 1 is 68%, while the PLS of Lot No. 2 is 80%. The seeding rate of Lot No. 1 would need to be increased by more than 12% to obtain the same number of PLS as in Lot No. 2. Turfgrass seeding rates (Tables 2–11) are expressed on a PLS basis. Therefore, to determine how much seed to purchase for the best stand of grass, adjust the seeding rate according to the percent PLS of each seed lot.
Table 1. Average number of seeds per pound for common Pacific Northwest turfgrasses.
| Grass | Seeds |
|---|---|
| Streambank wheatgrass (Elymus lanceolatus ssp. lanceolatus) | 156,000 |
| Tall fescue (Festuca arundinacea and Lolium arundinaceum) | 178,000–234,000 |
| Perennial ryegrass (Lolium perenne) | 210,000–270,000 |
| Crested wheatgrass (Agropyron cristatum) | 311,000 |
| Red fescue (creeping) (Festuca rubra var. rubra) | 365,000 |
| Chewings fescue (Festuca rubra var. commutata) | 449,000 |
| Sheep or Idaho fescue (Festuca ovina or Festuca idahoensis) | 530,000 |
| Hard fescue (Festuca ovina var. duriuscula) | 592,000 |
| Kentucky bluegrass (Poa pratensis) | 1,022,000–1,758,000 |
| Colonial bentgrass (Agrostis tenuis) | 6,130,000 |
| Creeping bentgrass (Agrostis palustris and stolonifera) | 6,130,000 |
| Velvet bentgrass (Agrostis canina) | 8,247,000 |
Table 2. Seeding recommendations for new golf course putting greens.
| Grass | Seeding rate (lb/1,000 ft2) |
|---|---|
| Creeping bentgrass varieties* | 1–2 |
| Velvet bentgrass | 1–2 |
| *See the websites listed at the end of this bulletin for the most recent bentgrass variety rankings from WSU, OSU, UI, and NTEP. | |
Table 3. Seeding recommendations for new golf course teeing grounds.
| Grass | Seeding rate(lb/1,000 ft2) | Western Washington and Western Oregon | Idaho, Eastern Washington, and Eastern Oregon |
|---|---|---|---|
| Perennial ryegrass | 5–8 | R* | R |
| Kentucky bluegrass | 3 | NR** | R |
| Creeping bentgrass | 2 | R | R |
| Perennial ryegrass | 4 | NR | R |
|
-plus Kentucky bluegrass |
1.5 | NR | R |
| Perennial ryegrass | 5 | R | R |
|
-plus bentgrass |
1 | R | R |
|
*Recommended. **Not recommended unless as part of a mixture. |
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Table 4. Seeding recommendations for new golf course fairways.
| Grass* | Seeding rate(lb/1,000 ft2) | Western Washington and Western Oregon | Idaho, Eastern Washington, and Eastern Oregon |
|---|---|---|---|
| Kentucky bluegrass (blended varieties) | 3 | NR** | R*** |
| Kentucky bluegrass (blended varieties) | 2 | NR | R |
|
-plus creeping red, Chewings, or hard fescue |
1 | NR | R |
| Kentucky bluegrass | 2 | NR | R |
| -plus perennial ryegrass | 2 | NR | R |
| Perennial ryegrass (blended varieties) | 5–8 | R | R |
| Perennial ryegrass | 2 | R | R |
|
-plus creeping red, Chewings, or hard fescue |
2 | R | R |
|
-plus colonial bentgrass**** |
0.5 | R | R |
| Perennial ryegrass | 1 | R | R |
|
-plus creeping red, Chewings, or hard fescue |
1 | R | R |
| -plus Kentucky bluegrass | 1 | R | R |
|
-plus colonial bentgrass**** |
0.5 | R | R |
| Creeping red, hard, or Chewings fescue | 3 | R | R |
| -plus colonial bentgrass | 0.75 | R | R |
| Perennial ryegrass | 3 | R | R |
|
-plus colonial bentgrass**** |
0.5 | R | R |
|
*Never plant bentgrasses on fairways in eastern Washington, eastern Oregon, or Idaho unless mowing heights are maintained at less than 5/8 inch and fungicides are used to control snow mold. **Not recommended. ***Recommended. ****Colonial bentgrass will most likely dominate when added to these mixtures. Take care to match the grass colors and growth habits to avoid a mottled and bouncy appearance. |
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Table 5. Seeding recommendations for new athletic fields.
| Grass | Seeding rate(lb/1,000 ft2) | Western Washington and Western Oregon | Idaho, Eastern Washington, and Eastern Oregon |
|---|---|---|---|
| Kentucky bluegrass (blended varieties) | 3 | NR* | R** |
| Kentucky bluegrass (blended varieties) | 2 | R | R |
|
-plus perennial ryegrass |
2 | R | R |
| Perennial ryegrass (blended varieties) | 5–8 | R | NR |
|
*Not recommended for lower maintenance fields. **Recommended. |
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Table 6. Seeding recommendations for new home lawns, parks, and cemeteries*.
| Grass** | Seeding rate(lb/1,000 ft2) | Western Washington and Western Oregon | Idaho, Eastern Washington, and Eastern Oregon |
|---|---|---|---|
| Kentucky bluegrass (blended varieties) | 3 | NR*** | R**** |
| Kentucky bluegrass (blended varieties) | 1.5 | NR | R |
|
-plus creeping red, Chewings, or hard fescue |
1.5 | NR | R |
| Kentucky bluegrass (blended varieties) | 2 | R | R |
|
-plus creeping red, Chewings, or hard fescue |
1 | R | R |
|
-plus perennial ryegrass |
1–2 | R | R |
| Perennial ryegrass | 4 | R | R |
|
-plus creeping red, Chewings, or hard fescue |
2 | R | R |
| Creeping red, Chewings, or hard fescue | 3 | R | NR |
|
-plus colonial bentgrass |
1 | R | NR |
| Turf-type ryegrass | 5–8 | R | NR |
| Colonial bentgrass | 0.75–1.5 | R | NR |
| Creeping red, Chewings, or hard fescue | 3 | R | R |
| Tall fescue | 8 | limited use; must be overseeded to maintain stand density | R |
|
*In cemeteries with large numbers of existing or planned trees, plant seed mixtures containing 35–50% creeping red, Chewings, or hard fescues by weight. **Maintain lawns seeded with fine fescue and bentgrass in western Washington and western Oregon at 1/2–3/4 inch mowing height for maximum beauty and thatch control. Seeding eastern Washington, eastern Oregon, or Idaho lawns to bentgrass is not recommended. ***Not recommended. ****Recommended. |
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Table 7. Overseeding recommendations for putting greens and teeing grounds.
| Grass | Seeding rate(lb/1,000 ft2) | Western Washington and Western Oregon | Idaho, Eastern Washington, and Eastern Oregon |
|---|---|---|---|
| Putting greens | |||
|
Creeping or velvet bentgrass |
1–2 | R* | R |
| Tees | |||
|
Kentucky bluegrass |
3 | NR** | R |
|
Perennial ryegrass |
6 | R | R |
|
Perennial ryegrass |
6 | R | R |
|
-plus any bentgrass |
1 | R | R |
|
Any bentgrass |
1–2 | R | R |
|
*Recommended. **Not recommended. |
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Seed tag. In addition to germination, purity, and turfgrass species, the seed tag must show percentages of weeds, other crop seed, inert matter, and the date of the last germination test. If you buy Washington, Idaho, or Oregon certified seed, you can be confident that particular lot meets good seed standards. Some noncertified seed may be better than average quality certified seed, but you cannot always be certain of its genetic origin.
Blend. Seed blends contain two or more varieties of a single species.
Mixture. Seed mixtures contain two or more turfgrass species. An example of a simple mixture is one variety of Kentucky bluegrass combined with one variety of perennial ryegrass, while a complex mixture would be blends of several Kentucky bluegrass varieties and several perennial ryegrass varieties. In Tables 3–8, the recommended mixtures are identified with “plus” between species.
Overseeding Turfgrass Areas
Overseeding is the application of seed to depleted turfgrass areas where optimum seedbed preparation or cultivation cannot be accomplished. Overseeding strengthens or reestablishes turfgrass stands in small bare areas, increases the density of established turf, or infuses new varieties or different types of grasses into established turfgrass stands. The overseeding rates in Tables 7–10 are standard recommendations; individual site characteristics such as soil type, time of year, and cultural practices may affect these numbers slightly.
Roadside and Slope Stabilization
Grasses or grass and legume mixtures are widely used to establish vegetation along roadsides and stabilize erodible slopes; see Table 11 for common types of grasses that work well for this purpose. Wheatgrasses have excellent seedling vigor and compete well against weeds east of the Cascades. If irrigation will not be provided, plant wheatgrasses in early spring or as a late fall dormant seeding.
Table 8. Overseeding recommendations for golf course fairways.
| Grass | Seeding rate(percentage by weight)* | Western Washington and Western Oregon | Idaho, Eastern Washington, and Eastern Oregon |
|---|---|---|---|
| Perennial ryegrass | 50 | NR** | R*** |
|
-plus Kentucky bluegrass |
50 | NR | R |
| Perennial ryegrass | 80 | R | R |
|
-plus colonial bentgrass |
20 | R | R |
|
*Overseeding rates can vary from 75 to over 400 lb/acre. Contact your local Extension specialist for more information. **Not recommended. ***Recommended. |
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Table 9. Overseeding recommendations for home lawns, parks, and cemeteries.
| Grass | Seeding rate(lb/1,000 ft2) | Western Washington and Western Oregon | Idaho, Eastern Washington, and Eastern Oregon |
|---|---|---|---|
| Perennial ryegrass | 6 | R* | R |
| Perennial ryegrass | 4 | R | R |
|
-plus creeping red, Chewings, or hard fescue |
2 | R | R |
| Creeping red, Chewings, or hard fescue | 2 | R | NR** |
| -plus colonial bentgrass | 0.5 | R | NR |
| Kentucky bluegrass (blended varieties) | 2 | NR | R |
| Kentucky bluegrass (blended varieties) | 1 | NR | R |
|
-plus creeping red, Chewings, or hard fescue |
2 | NR | R |
| Perennial ryegrass | 4 | NR | R |
|
-plus Kentucky bluegrass |
1.5 | NR | R |
| Tall fescue | 6–8 | limited use | R |
|
*Recommended. **Not recommended. |
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Table 10. Overseeding recommendations for athletic fields.
| Grass | Seeding rate(lb/1,000 ft2) | Western Washington and Western Oregon | Idaho, Eastern Washington, and Eastern Oregon |
|---|---|---|---|
| Perennial ryegrass | 6 | R* | R |
| Perennial ryegrass | 4 | R | R |
|
-plus Kentucky bluegrass** |
1.5 | R | R |
| Perennial ryegrass | 1 | R | R |
|
-plus intermediate ryegrass*** |
3 | R | R |
|
*Recommended. **Kentucky bluegrass seedlings are extremely poor competitors during establishment. If turfgrasses cover as much as 50% of the ground, seed turf-type perennial ryegrasses alone since Kentucky bluegrasses will not compete favorably. ***Use intermediate ryegrass very early or late during the seasons when soil temperatures are too cool to get quick cover by perennial ryegrass or Kentucky bluegrass. Intermediate ryegrass will act as a biennial in most cases. |
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Table 11. Seeding recommendations for roadside and slope stabilization*.
| Grass | Seeding rate(lb/1,000 ft2) | Western Washington and Western Oregon | Idaho, Eastern Washington, and Eastern Oregon |
|---|---|---|---|
| Crested wheatgrass** | 0.5–1.0 | NR*** | R**** |
| Streambank wheatgrass** | 1 | NR | R |
| Hard fescue***** | 1 | NR | R |
| Hard fescue | 0.35 | NR | R |
| -plus crested wheatgrasse | 0.5 | NR | R |
| Sheep or Idaho fescue***** | 1 | NR | R |
| Common or improved perennial ryegrass | 1.5 | R | R |
|
-plus creeping red or Chewings fescue |
1 | R | NR |
| Common or improved perennial ryegrass | 1.5 | R | NR |
|
-plus creeping red or Chewings fescue |
1 | R | NR |
| -plus white Dutch clover | 0.1 | R | NR |
| Colonial bentgrass can be added to the two preceding entries for wet sites | 0.25 | R | NR |
|
*These rates are based upon prepared seedbeds seeded with a brillion drill or hydroseeding methods. **On nonirrigated 8–15 inch rainfall areas, crested wheatgrass and streambank wheatgrass perform very well. ***Not recommended. ****Recommended. *****On nonirrigated 15–25 inch rainfall areas, sheep, hard, or Idaho fescue and crested wheatgrass perform well. |
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Authors: G.K. Stahnke, Associate Extension Agronomist, and E.D. Miltner, Associate Research Agronomist, Washington State University, Puyallup; R.C. Golembiewski, Assistant Professor of Horticulture, Oregon State University, Corvallis; T.A. Salaiz, Turfgrass Extension Specialist, University of Idaho, Aberdeen; and W.J. Johnston, Professor of Crop Science, WSU, Pullman.
Websites with the most recent bentgrass variety rankings
Washington State University: http://turf.wsu.edu/; http://www.puyallup.wsu.edu/turf
Oregon State University: http://www.BeaverTurf.com
University of Idaho: http://www.extension.uidaho.edu/idahogardens/
National Turfgrass Evaluation Program: http://www.ntep.org
Pacific Northwest Extension publications are produced cooperatively by the three Pacific Northwest land-grant universities: Washington State University, Oregon State University, and the University of Idaho. Similar crops, climate, and topography create a natural geographic unit that crosses state lines. Since 1949, the PNW program has published more than 600 titles, preventing duplication of effort, broadening the availability of faculty specialists, and substantially reducing costs for the participating states.
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Copyright 2010 Washington State University.
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Published and distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914, by Washington State University Extension, Oregon State University Extension Service, University of Idaho Cooperative Extension System, and the U.S. Department of Agriculture cooperating. WSU Extension programs, activities, materials, and policies comply with federal and state laws and regulations on nondiscrimination regarding race, sex, religion, age, color, creed, and national or ethnic origin; physical, mental, or sensory disability; marital status or sexual orientation; and status as a Vietnam-era or disabled veteran. Washington State University Extension, The Oregon State University Extension Service, and University of Idaho Extension are Equal Opportunity Employers. Evidence of noncompliance may be reported through your local Extension office. Trade names have been used to simplify information; no endorsement is intended. Revised December 2010.
PNW299