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When to Plant Garlic in Multnomah County, OR

Garlic is a pungent allium planted in fall and harvested the following summer. Hardneck varieties produce edible flower stalks (scapes) and are more cold-hardy.

Multnomah County, Oregon is in USDA Zone 8b. The average last spring frost is April 14 and the first fall frost is October 27, giving you a growing season of approximately 196 days.

At an elevation of 357 feet, Multnomah County receives approximately 35.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Garlic to ensure they mature before fall.

Multnomah County, OR (Zone 8b) Moderate season
196 days
Last Spring Frost April 14
196 growing days
First Fall Frost October 27

Multnomah County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Apr 8 🍅 Harvest: Jul 8 – Dec 23
Recommended (50%) ✗ May not fit
Transplant: Apr 14 🍅 Harvest: Jul 14 – Dec 29
Safe Start (90%) ✓ Fits season (300 days to spare)
Transplant: May 9 🍅 Harvest: Aug 8 – Jan 23

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 926 gal / 100 sq ft
Garlic needs ~2,145 GDD — county provides 2,548 GDD Good fit

Garlic Planting Timeline โ€” Multnomah County, OR

Garlic Planting Calendar

Activity When Date Range
Fall Sowing September 15 Sep 15 โ€“ Sep 29

Plant 1" deep ยท 6" apart ยท Rows 12" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May โ€”
June โ€”
July โ€”
August โ€”
September Fall Sowing
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

90โ€“240 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 8b

Growing Season

196 days

Growing Tips for Multnomah County

Plant individual cloves pointed end up in fall, 6 weeks before ground freezes. Mulch heavily with straw. Harvest when lower leaves begin to brown but 5-6 green leaves remain.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans
  • Asparagus

Level Up Your Garden

Frequently Asked Questions

When should I plant Garlic in Multnomah County, OR?

Multnomah County is in Zone 8b with an average last frost of April 14. Plan your Garlic planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Multnomah County, OR?

Multnomah County, Oregon is in USDA Hardiness Zone 8b. The average last spring frost is April 14 and first fall frost is October 27.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Multnomah County gardeners in Zone 8b organize planting dates, track what's growing, and never miss a planting window.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Multnomah County, OR. Local conditions may vary. Last updated: April 2026.