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When to Plant Garlic in Polk 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.

Polk County, Oregon is in USDA Zone 8a. The average last spring frost is April 10 and the first fall frost is October 31, giving you a growing season of approximately 204 days.

At an elevation of 331 feet, Polk County receives approximately 54.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81ยฐF, so choose short-season varieties of Garlic to ensure they mature before fall. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Garlic root diseases.

Polk County, OR (Zone 8a) Long season
204 days
Last Spring Frost April 10
204 growing days
First Fall Frost October 31

Polk County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Mar 24 🍅 Harvest: Jun 23 – Dec 8
Recommended (50%) ✗ May not fit
Transplant: Apr 10 🍅 Harvest: Jul 10 – Dec 25
Safe Start (90%) ✓ Fits season (316 days to spare)
Transplant: May 2 🍅 Harvest: Aug 1 – Jan 16

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
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Garlic needs ~1,774 GDD — county provides 2,193 GDD Good fit

Garlic Planting Timeline โ€” Polk County, OR

Garlic Planting Calendar

Activity When Date Range
Fall Sowing September 19 Sep 19 โ€“ Oct 3

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 Fall Sowing
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 8a

Growing Season

204 days

Growing Tips for Polk 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 Polk County, OR?

Polk County is in Zone 8a with an average last frost of April 10. Plan your Garlic planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Polk County, OR?

Polk County, Oregon is in USDA Hardiness Zone 8a. The average last spring frost is April 10 and first fall frost is October 31.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Polk County gardeners in Zone 8a 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 Polk County, OR. Local conditions may vary. Last updated: April 2026.