Soil Resources for Pacific Northwest Gardeners

If you want to grow healthy plants, you need to build healthy soil.

Healthy soil is full of nutrients, microorganisms and organic matter. It has good drainage and water holding capacity and helps keep the water and air free of pollutants. Improve the quality of your soil by adding compost and mulch. Before you add fertilizer, test your soil to find out what your garden needs and make sure the soil is free of contaminants. You can build healthy soil by planting cover crops, using a “no-till” technique such as sheet mulching or straw bale gardening, and rotating your crops to prevent attacks from pests and disease. Delve into the resources we have gathered together for you to find the things you need get growing this spring!

Soil Testing

King Conservation District Soil Testing Program

Tests for fertility, pH, and organic matter. Does not include testing for heavy metals.

Free testing for landowners who reside within the eligibility area, one time only, five samples.

Additional soil tests can be added for a fee. (425) 282-1905 or (425) 282-1900


UMass Extension Soil & Plant Tissue Testing Laboratory, Amherst, MA

Tests for fertility, pH, cation exchange, lead and aluminum. Extra charges for organic matter and soluble salts. (413) 545-2311


Cascade Analytical, Inc

Tests for fertility, organic matter, pH, and soluble salts. Extra charges for lead and arsenic. (800) 545-4206


Soiltest Farm Consultants, Inc.

Offers a variety of tests for fertility, heavy metals and other elements. (800) 765-1622 or Local (509) 765-1622


Kuo Testing Labs, Inc.

Offers a variety of tests for fertility, heavy metals and other elements. Toll Free (800) 328-0112 or Local (509) 488- 0112


Edge Analytical Laboratories

Tests for heavy metals, bacteria, pesticides and other contaminants. (800) 755-9295

Sheet Mulching and Straw Bale Gardening

King County Native Plants

Agroforestry Sheet Mulching

No Dig Straw Bale Garden


Find local sources of arborist chips, organic straw bales, cardboard or burlap bags:

Chipdrop, free chips from local arborists – sign up service

The Garden Hotline, (206) 633-0224,

Cover Crops

Mail Order:

Fedco Seed Company,  (207) 426-9900

Johnny’s Selected Seeds,  (877) 564-6697

Osborn Seed Company, (360) 424- 7333 Canadian rep (607) 518- 6953

Peaceful Valley Farm Supply,  (888) 784-1722

Territorial Seed Company,  (800) 626-0866

Local Retail – King County:

Bellevue Nursery,  (425) 454-5531

McLendon’s Hardware,  Renton (425) 235-3555 Woodinville (425) 485-1363

Molbak’s Nursery,  (425) 483-5000

The Grange in Issaquah, (425) 392-6469

Local Retail: Seattle:

City People’s Garden Store, (206) 324-0737

Magnolia Garden Center,   (206) 284-1161

Sky Nursery,  (206) 546-4851

Swansons Nursery,  (206) 782-2543

Walt’s Organic Fertilizer Co.,  (206) 297-9092

West Seattle Nursery, (206) 935-9276

Certified Organic Soil Products


Bailey Compost, (360) 568-8826

Cedar Grove Composting,  (877) 764-5748

DirtExchange, (206) 599-3478 (carries Cedar Grove products)

Sky Nursery, (206) 546-4851 (carries Cedar Grove products)

Yelm Earthworm & Castings Farm, (877) 339-6767


Black Gold OMRI certified products – available at local retail stores including Fred Meyer

Cedar Grove Compost & Potting Soil – available at local retail stores

Zoo Doo compost. Call the ZooStore at (206) 548-1535 to check for availability.

Organic Fertilizer Sources

Walt’s Organic Fertilizer Co.,  (206) 297-9092. Granular certified organic ‘Rainy Pacific NW Blend’ fertilizer and others blended for local conditions.

Hendrickus Organics, 425) 392-9977. Granular certified organic fertilizers and soil conditioners blended for local conditions.

Dr. Earth, Granular and liquid fertilizers

E.B. Stone, Granular and liquid fertilizers

Neptune’s Harvest, Granular and liquid fertilizers

WISErganic, All-purpose organic liquid fertilizers made from food scraps collected at PCC Natural Markets and made into fertilizer in Issaquah.

Wiser Worm Farm, Worm tea fertilizer made from certified organic worm castings.

Crop Rotation for Integrated Pest Management and Fertility

“The Maritime Northwest Garden Guide”, Tilth Alliance, rev. ed., 2014.

“Your Farm in the City”, Lisa Taylor, 2011, Black Dog and Leventhal Publishers, Inc.

“Growing Vegetables West of the Cascades”, Steve Solomon, 2007, Sasquatch Books.

Leave a Reply