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When to Plant Thai Basil in Linn County, OR

Thai basil has a distinctive anise-licorice flavor with sturdy purple stems and small leaves. It is essential in Thai, Vietnamese, and other Southeast Asian cuisines.

Linn County, Oregon is in USDA Zone 8a. The average last spring frost is April 22 and the first fall frost is October 25, giving you a growing season of approximately 186 days.

At an elevation of 259 feet, Linn County receives approximately 37.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81ยฐF, so choose short-season varieties of Thai Basil to ensure they mature before fall.

Linn County, OR (Zone 8a) Moderate season
186 days
Last Spring Frost April 22
186 growing days
First Fall Frost October 25

Linn County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (52 days to spare)
Start indoors: Feb 25 Transplant: Apr 29 🍅 Harvest: Jun 24 – Aug 26
Recommended (50%) ✓ Fits season (53 days to spare)
Start indoors: Mar 4 Transplant: May 6 🍅 Harvest: Jul 1 – Sep 2
Safe Start (90%) ✓ Fits season (56 days to spare)
Start indoors: Mar 27 Transplant: May 29 🍅 Harvest: Jul 24 – Sep 25

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
0.2″/week
Watering frequency Only during dry spells
Season total 265 gal / 100 sq ft
Thai Basil needs ~672 GDD — county provides 1,999 GDD Excellent fit

Thai Basil Planting Timeline โ€” Linn County, OR

Thai Basil Planting Calendar

Activity When Date Range
Start Indoors March 4 Mar 4 โ€“ Mar 18
Transplant Outdoors May 6 May 6 โ€“ May 20
Direct Sow April 29 Apr 29 โ€“ May 20
Harvest July 1 Jul 1 โ€“ Sep 2

Plant 0.5" deep ยท 8" apart ยท Rows 12" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April Direct Sow
May Transplant Outdoors Direct Sow
June โ€”
July Harvest
August Harvest
September Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

50โ€“75 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 8a

Growing Season

186 days

Growing Tips for Linn County

Start seeds indoors or direct sow after last frost. Thai basil holds up better to heat in cooking than sweet basil. Pinch flowers to prolong leaf production.

Companion Planting

Good Companions

Avoid Planting Near

  • Rue
  • Sage

Level Up Your Garden

Frequently Asked Questions

When should I plant Thai Basil in Linn County, OR?

Linn County is in Zone 8a with an average last frost of April 22. Plan your Thai Basil planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Linn County, OR?

Linn County, Oregon is in USDA Hardiness Zone 8a. The average last spring frost is April 22 and first fall frost is October 25.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Linn 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 Linn County, OR. Local conditions may vary. Last updated: April 2026.