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When to plant Thai Basil in Applegate, CA

Plant Thai Basil in Applegate after April 22; the prime window is April 29–May 20.

When to Plant Thai Basil in Applegate, CA

Placer County, California Zone 9b July

July to-do list for Placer County, California

July is a pivotal month for Placer County, California gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 22
Avg. first frost November 9
Soil temp (4") 88°F
Watering Critical
Pest pressure High
Daylight 14.5 hrs

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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.

Applegate, California is in USDA Zone 9b. The average last spring frost is April 22 and the first fall frost is November 9, giving you a growing season of approximately 201 days.

At an elevation of 651 feet, Placer County receives approximately 25.3 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Thai Basil during the growing season.

Applegate, CA (Zone 9b) Long season
201 days
Last Spring Frost April 22
201 growing days
First Fall Frost November 9

Applegate Soil Profile

Soil Type

Loam

Soil pH

6.6-7.2

Drainage

Well Drained

Thai Basil Planting Risk Windows

Early Start (70% safe) ✓ Fits season (74 days to spare)
Start indoors: Mar 3 Transplant: Apr 21 🍅 Harvest: Jun 16 – Aug 18
Recommended (50%) ✓ Fits season (75 days to spare)
Start indoors: Mar 11 Transplant: Apr 29 🍅 Harvest: Jun 24 – Aug 26
Safe Start (90%) ✓ Fits season (69 days to spare)
Start indoors: Apr 16 Transplant: Jun 4 🍅 Harvest: Jul 30 – Oct 1

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 Applegate

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

Soil pH

Your soil pH (6.6–7.2) overlaps with Thai Basil's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Thai Basil.

Organic Matter

Organic matter is moderate (3.1%). Annual compost additions will help Thai Basil.

How to Plant Thai Basil

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

Succession Planting Thai Basil

4
successive plantings in your 201-day season

Sow every 5.7 weeks. Last sowing by Aug 26 to harvest before frost.

Thai Basil Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 1,656 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Thai Basil

Thai Basil needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Thai Basil Needs Rainfall You Supplement Action
Jan 5.2" 0" ❄️ Dormant
Feb 5.3" 0" ❄️ Dormant
Mar 4.2" 0" ❄️ Dormant
Apr 4.3" 1.7" 2.6" 🚿 Regular watering
May 4.3" 0.7" 3.6" 🚿 Regular watering
Jun 4.3" 0.1" 4.2" 🚿 Regular watering
Jul 4.3" 0" 4.3" 🚿 Regular watering
Aug 4.3" 0" 4.3" 🚿 Regular watering
Sep 4.3" 0.2" 4.1" 🚿 Regular watering
Oct 4.3" 1.1" 3.2" 🚿 Regular watering
Nov 4.3" 2.4" 1.9" 💧 Light watering
Dec 4.4" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in Placer County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Thai 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.

Thai Basil needs ~859 GDD — county provides 2,763 GDD Excellent fit

Thai Basil Planting Timeline — Applegate, CA

Thai Basil Planting Calendar

Activity When Date Range
Start Indoors March 11 Mar 11 – Mar 25
Transplant Outdoors April 29 Apr 29 – May 13
Direct Sow April 29 Apr 29 – May 20
Harvest June 24 Jun 24 – Aug 26

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

50–75 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 9b

📆 Growing Season

201 days in Placer County

Growing Tips for Thai Basil in Applegate

Direct sow Thai Basil outdoors after April 22 in Placer County when soil has warmed and frost danger has passed.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

When should I plant Thai Basil in Applegate, CA?

In Applegate, CA, plant Thai Basil after the last frost (around April 22) and before the first frost (around November 9). Best results when soil holds above 50°F.

What growing zone is Applegate, CA for Thai Basil?

Applegate sits in USDA Zone 9b. Thai Basil grows reliably in zones 4a through 11b, so it's a good fit here.

Can Thai Basil grow in Applegate's climate?

Yes — Thai Basil grows well in Applegate's temperate climate. Applegate averages a 201-day frost-free season, with last frost around April 22 and first frost around November 9.

🌱

Your Placer County Garden Planner — Free

A 22-page printable planner built for Placer County (Zone 9b). 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 Placer County, CA. Local conditions may vary. Last updated: July 2026.