Multnomah County, OR Extension Office & Soil Testing Directory
Welcome to the official directory resource for Multnomah County, OR. Connecting local homeowners, urban gardeners, and commercial growers with Oregon's land-grant university extension resources, state soil testing lab services, and Master Gardener volunteer clinics.
1. Extension Office Contact Details & Operational Hours
The OSU Extension Service - Multnomah County serves as the primary educational extension center in Multnomah County. Visit or call during standard operational hours for agricultural advice, soil sample kits, and youth 4-H programs.
| Official Office Name: | OSU Extension Service - Multnomah County |
| Physical Address: | 520 SE Columbia River Drive, Suite 160, Vancouver, WA 98661 (Metro Office) |
| Direct Phone Desk: | (503) 655-8631 |
| Email Contact: | multnomah.extension@oregonstate.edu |
| Office Hours: | Monday – Friday: 8:00 AM – 5:00 PM |
| Official Web Portal: | https://extension.oregonstate.edu/multnomah |
2. Official Soil Testing Laboratory & Pricing
Testing your soil is the single most important step before adding fertilizers or agricultural lime. The official testing laboratory serving Multnomah County is OSU Recommended PNW Soil Testing Laboratories.
| Official Testing Lab: | OSU Recommended PNW Soil Testing Laboratories |
| Lab Location: | Submittal guide EC 628 at Metro office |
| Routine Sample Fee: | $20 – $30 routine PNW sample |
| Expected Turnaround: | 5 to 7 business days |
| Official Lab Website: | https://extension.oregonstate.edu/catalog/pub/ec-628-how-do-i-get-my-soil-tested |
How to Collect and Submit a Soil Sample in Multnomah County:
- Pick up a Soil Kit: Pick up official sample boxes and submittal forms at the OSU Extension Service - Multnomah County (520 SE Columbia River Drive, Suite 160, Vancouver, WA 98661 (Metro Office)).
- Collect Sub-Samples: Use a clean stainless steel trowel to take 10 to 12 soil cores from a 4-to-6-inch depth across your garden or lawn area.
- Air-Dry: Mix sub-samples in a clean plastic bucket and air-dry on clean paper at room temperature (never use an oven).
- Submit Sample: Return your filled soil box to the extension office or mail directly to OSU Recommended PNW Soil Testing Laboratories.
3. Master Gardener Volunteer Program & Plant Clinic
The Multnomah County Master Gardeners provides free plant disease diagnostics, lawn care advice, and eco-friendly pest management tips.
| Program Name: | Multnomah County Master Gardeners |
| Plant Clinic Hours: | Monday – Friday: 9:00 AM – 4:00 PM (Note: Plant clinics run seasonally; call office during winter months) |
| Direct Helpline Phone: | (503) 655-8631 |
| Program Portal: | https://multnomahmastergardeners.org/ |
Volunteer Training: Oregon State University PNW horticulture course.
4. Regional Soil & Growing Snapshot for Multnomah County
USDA Plant Hardiness Zone: Zone 8b
Natural Soil Profile: Willamette Valley Silt Loam & Basaltic Clay
Popular Local Crops: Berries, hazelnuts, tomatoes, cool-season greens, lawns
Extension Specialist Tip: Pacific Northwest winter rains leach calcium; test soil pH every 2 years and add agricultural lime.
5. 🧮 Interactive Soil Amendment Calculator for Multnomah County
Estimate the recommended agricultural limestone or elemental sulfur needed to adjust your garden soil pH based on local Willamette Valley Silt Loam & Basaltic Clay characteristics.
📚 Recommended Extension Guides & Soil Articles
Learn more about interpreting your Multnomah County extension soil test report and managing plant nutrients:
Frequently Asked Questions (Multnomah County Directory)
The OSU Extension Service - Multnomah County is located at 520 SE Columbia River Drive, Suite 160, Vancouver, WA 98661 (Metro Office). You can call their main desk directly at (503) 655-8631 during standard business hours (Monday – Friday: 8:00 AM – 5:00 PM).
Standard soil analysis for Multnomah County garden samples through OSU Recommended PNW Soil Testing Laboratories costs $20 – $30 routine PNW sample. Check with the office for special sample types.
You can reach the Multnomah County Master Gardeners hotline by calling (503) 655-8631 during plant clinic hours (Monday – Friday: 9:00 AM – 4:00 PM).
Multnomah County falls primarily within USDA Plant Hardiness Zone 8b. Local soil is characterized as Willamette Valley Silt Loam & Basaltic Clay.
Written & Verified by Sahajul
Verified Author & Founder
Sahajul is an independent agricultural data researcher based in India and founder of LocalSoilLab.com. He specializes in compiling, structuring, and verifying US land-grant university extension services, soil lab testing fee schedules, and county Master Gardener contact directories directly from official .edu and USDA NIFA portals.