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When to Plant Basil in Santa Barbara County, CA

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.

Santa Barbara County, California is in USDA Zone 10a. The average last spring frost is February 28 and the first fall frost is November 24, giving you a growing season of approximately 269 days.

At an elevation of 2,364 feet, Santa Barbara County receives approximately 19.9 inches of rainfall annually with predominantly loam soil. Summer highs average 89ยฐF, providing good warmth for Basil during the growing season. With low rainfall, drip irrigation is essential for growing Basil successfully. Mulch heavily to conserve soil moisture.

Santa Barbara County, CA (Zone 10a) Long season
269 days
Last Spring Frost February 28
269 growing days
First Fall Frost November 24

Santa Barbara County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (147 days to spare)
Start indoors: Jan 1 Transplant: Feb 19 🍅 Harvest: Apr 16 – Jun 18
Recommended (50%) ✓ Fits season (143 days to spare)
Start indoors: Jan 17 Transplant: Mar 7 🍅 Harvest: May 2 – Jul 4
Safe Start (90%) ✓ Fits season (131 days to spare)
Start indoors: Feb 24 Transplant: Apr 14 🍅 Harvest: Jun 9 – Aug 11

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 Santa Barbara County

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

Soil pH

Your soil pH (6.5โ€“7.2) overlaps with Basil's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help Basil.

How to Plant Basil

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

Succession Planting Basil

6
successive plantings in your 269-day season

Sow every 5.7 weeks. Last sowing by Sep 10 to harvest before frost.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
0.3″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 838 gal / 100 sq ft
Drought risk

Water stress score is 10/10 โ€” consider drought-tolerant varieties and mulching

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€” 4" 0" โ„๏ธ Dormant
Feb 2.6" 4.6" 0" โœ… Rainfall sufficient
Mar 2.6" 2.9" 0" โœ… Rainfall sufficient
Apr 2.6" 1.8" 0.8" ๐Ÿ’ง Light watering
May 2.6" 0.5" 2.1" ๐Ÿšฟ Regular watering
Jun 2.6" 0.1" 2.5" ๐Ÿšฟ Regular watering
Jul 2.6" 0" 2.6" ๐Ÿšฟ Regular watering
Aug 2.6" 0" 2.6" ๐Ÿšฟ Regular watering
Sep 2.6" 0.2" 2.4" ๐Ÿšฟ Regular watering
Oct 2.6" 0.8" 1.8" ๐Ÿšฟ Regular watering
Nov 2.6" 2.1" 0.5" ๐Ÿ’ง Light watering
Dec โ€” 2.9" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Febโ€“Nov in Santa Barbara 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 4,522 GDD Excellent fit

Basil Planting Timeline โ€” Santa Barbara County, CA

Basil Planting Calendar

Activity When Date Range
Start Indoors January 17 Jan 17 โ€“ Jan 31
Transplant Outdoors March 7 Mar 7 โ€“ Mar 21
Direct Sow March 7 Mar 7 โ€“ Mar 28
Harvest May 2 May 2 โ€“ Jul 4

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

Month-by-Month Timeline

MonthActivities
January Start Indoors
February โ€”
March Transplant Outdoors Direct Sow
April โ€”
May Harvest
June Harvest
July Harvest
August โ€”
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 1-2 times/week

๐Ÿ“… Days to Maturity

50โ€“75 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 10a

๐Ÿ“† Growing Season

269 days in Santa Barbara County

Growing Tips for Basil in Santa Barbara County

Direct sow Basil outdoors after February 28 in Santa Barbara 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 Santa Barbara County, CA?

Santa Barbara County is in Zone 10a with an average last frost of February 28. Plan your Basil planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Santa Barbara County, CA?

Santa Barbara County, California is in USDA Hardiness Zone 10a. The average last spring frost is February 28 and first fall frost is November 24.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Santa Barbara County gardeners in Zone 10a 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 Santa Barbara County, CA. Local conditions may vary. Last updated: April 2026.