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When to Plant Basil in Josephine County, OR

Josephine County, Oregon Zone 8b May

Your May gardening checklist

Each item below is timed to Josephine County, Oregon's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 22
Avg. first frost October 20
Soil temp (4") 69°F
Watering High
Pest pressure High
Daylight 14.4 hrs
  1. Time to transplant basil

    Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.

Looking ahead to June
  • Starting indoors: basil

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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.

Josephine County, Oregon is in USDA Zone 8b. The average last spring frost is April 22 and the first fall frost is October 20, giving you a growing season of approximately 181 days.

At an elevation of 340 feet, Josephine County receives approximately 52.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Basil during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Basil root diseases.

Josephine County, OR (Zone 8b) Moderate season
181 days
Last Spring Frost April 22
181 growing days
First Fall Frost October 20
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Josephine County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (50 days to spare)
Start indoors: Feb 19 Transplant: Apr 23 🍅 Harvest: Jun 18 – Aug 20
Recommended (50%) ✓ Fits season (48 days to spare)
Start indoors: Mar 4 Transplant: May 6 🍅 Harvest: Jul 1 – Sep 2
Safe Start (90%) ✓ Fits season (60 days to spare)
Start indoors: Mar 24 Transplant: May 26 🍅 Harvest: Jul 21 – Sep 22

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 Josephine County

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

Soil pH

Your soil pH (5.7–6.2) is more acidic than Basil prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Josephine County is excellent for Basil — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.4%) — Basil will thrive.

How to Plant Basil

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

Succession Planting Basil

4
successive plantings in your 181-day season

Sow every 5.7 weeks. Last sowing by Aug 06 to harvest before frost.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
1.2″/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 8.4" 0" ❄️ Dormant
Feb 6.6" 0" ❄️ Dormant
Mar 6.2" 0" ❄️ Dormant
Apr 2.6" 3.6" 0" ✅ Rainfall sufficient
May 2.6" 2.7" 0" ✅ Rainfall sufficient
Jun 2.6" 2" 0.6" 💧 Light watering
Jul 2.6" 0.8" 1.8" 🚿 Regular watering
Aug 2.6" 0.9" 1.7" 🚿 Regular watering
Sep 2.6" 1.9" 0.7" 💧 Light watering
Oct 2.6" 4.4" 0" ✅ Rainfall sufficient
Nov 7.4" 0" ❄️ Dormant
Dec 8.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Josephine County). Supplement amounts are based on average rainfall — 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" — every day above 50°F 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 ~1,094 GDD — county provides 3,167 GDD Excellent fit

Basil Planting Timeline — Josephine County, OR

Basil Planting Calendar

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

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.6"/week · Natural rainfall sufficient

📅 Days to Maturity

50–75 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 8b

📆 Growing Season

181 days in Josephine County

Growing Tips for Basil in Josephine County

Direct sow Basil outdoors after April 22 in Josephine 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.

Recommended Basil Varieties for Josephine County

Downy mildew-resistant basil for your humid climate

Prospera (DM-resistant) Amazel Eleonora

Companion Planting

Good Companions

Avoid Planting Near

  • Rue
  • Sage

Check more plant combinations with our Companion Planting Checker →

🌾 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 35°F, under 45% humidity.

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

Frequently Asked Questions

When should I plant Basil in Josephine County, OR?

Josephine County is in Zone 8b with an average last frost of April 22. Plan your Basil planting based on this frost date — see the calendar above for exact timing.

What planting zone is Josephine County, OR?

Josephine County, Oregon is in USDA Hardiness Zone 8b. The average last spring frost is April 22 and first fall frost is October 20.

🌱

Your Josephine County Garden Planner — Free

A 24-page printable planner built for Josephine County (Zone 8b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Josephine County, OR. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.