Blog

When to Plant Basil in Coos County, OR

Basil is a fragrant warm-season herb essential to Italian and Thai cuisines. It comes in many varieties including sweet, Thai, purple, and lemon types.

Coos County, Oregon is in USDA Zone 8b. The average last spring frost is March 22 and the first fall frost is November 19, giving you a growing season of approximately 242 days.

At an elevation of 96 feet, Coos County receives approximately 38.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89ยฐF, providing good warmth for Basil during the growing season.

Coos County, OR (Zone 8b) Long season
242 days
Last Spring Frost March 22
242 growing days
First Fall Frost November 19

Coos County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (106 days to spare)
Start indoors: Jan 17 Transplant: Mar 21 🍅 Harvest: May 16 – Jul 18
Recommended (50%) ✓ Fits season (109 days to spare)
Start indoors: Feb 1 Transplant: Apr 5 🍅 Harvest: May 31 – Aug 2
Safe Start (90%) ✓ Fits season (104 days to spare)
Start indoors: Mar 4 Transplant: May 6 🍅 Harvest: Jul 1 – Sep 2

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.

Soil Compatibility in Coos County

How your county's soil matches Basil's growing requirements.

Soil pH

Your soil pH (5.4โ€“6.8) overlaps with Basil's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

The silt loam soil in Coos County is excellent for Basil โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.7%) โ€” Basil will thrive.

How to Plant Basil

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Basil

5
successive plantings in your 242-day season

Sow every 5.7 weeks. Last sowing by Sep 05 to harvest before frost.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
0.7″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Basil

Basil needs approximately 0.6 inches of water per week (2.6" per month). Here's how your county's rainfall compares month by month.

Month Basil Needs Rainfall You Supplement Action
Jan โ€” 5.5" 0" โ„๏ธ Dormant
Feb โ€” 4.5" 0" โ„๏ธ Dormant
Mar 2.6" 4.4" 0" โœ… Rainfall sufficient
Apr 2.6" 3.1" 0" โœ… Rainfall sufficient
May 2.6" 2.3" 0.3" ๐Ÿ’ง Light watering
Jun 2.6" 1.6" 1" ๐Ÿ’ง Light watering
Jul 2.6" 0.6" 2" ๐Ÿšฟ Regular watering
Aug 2.6" 0.8" 1.8" ๐Ÿšฟ Regular watering
Sep 2.6" 1.4" 1.2" ๐Ÿ’ง Light watering
Oct 2.6" 3.3" 0" โœ… Rainfall sufficient
Nov 2.6" 5.9" 0" โœ… Rainfall sufficient
Dec โ€” 5.5" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Marโ€“Nov in Coos County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Basil Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" โ€” every day above 50ยฐF deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Basil needs ~1,047 GDD — county provides 4,053 GDD Excellent fit

Basil Planting Timeline โ€” Coos County, OR

Basil Planting Calendar

Activity When Date Range
Start Indoors February 1 Feb 1 โ€“ Feb 15
Transplant Outdoors April 5 Apr 5 โ€“ Apr 19
Direct Sow March 29 Mar 29 โ€“ Apr 19
Harvest May 31 May 31 โ€“ Aug 2

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.6"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

50โ€“75 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 8b

๐Ÿ“† Growing Season

242 days in Coos County

Growing Tips for Basil in Coos County

Direct sow Basil outdoors after March 22 in Coos County when soil has warmed and frost danger has passed.

General growing tips

Start seeds indoors or direct sow after last frost. Pinch flower buds to extend leaf production. Harvest leaves from the top down, cutting just above a leaf pair.

Companion Planting

Good Companions

Avoid Planting Near

  • Rue
  • Sage

Check more plant combinations with our Companion Planting Checker →

๐ŸŒพ Save Your Own Basil Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Let flower spikes dry brown on the plant.
Storage Store airtight; viable 5 years at 35ยฐF, under 45% humidity.

Isolate 150 ft between varieties. Different basil species can cross.

Frequently Asked Questions

When should I plant Basil in Coos County, OR?

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

What planting zone is Coos County, OR?

Coos County, Oregon is in USDA Hardiness Zone 8b. The average last spring frost is March 22 and first fall frost is November 19.

๐ŸŒฑ

Plan Your Garden with Confidence

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

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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