When to Plant Basil in San Bernardino 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.
San Bernardino County, California is in USDA Zone 9a. The average last spring frost is February 24 and the first fall frost is November 25, giving you a growing season of approximately 274 days.
At an elevation of 1,012 feet, San Bernardino County receives approximately 16.9 inches of rainfall annually with predominantly loam soil. Summer highs average 97°F, so Basil may need afternoon shade and extra watering during peak heat. With low rainfall, drip irrigation is essential for growing Basil successfully. Mulch heavily to conserve soil moisture.
San Bernardino County Soil Profile
Soil Type
Loam
Soil pH
5.9-7.2
Drainage
Well Drained
Plant Planting Risk Windows
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 San Bernardino County
How your county's soil matches Basil's growing requirements.
Soil pH
Your soil pH (5.9–7.2) overlaps with Basil's range (6.0–7.0), though not a perfect match.
Soil Texture
The loam soil in San Bernardino County is excellent for Basil — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.4%). Annual compost additions will help Basil.
How to Plant Basil
Succession Planting Basil
Sow every 5.7 weeks. Last sowing by Sep 11 to harvest before frost.
Plant Water Budget
Water stress score is 10/10 — 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 | — | 3.2" | 0" | ❄️ Dormant |
| Feb | 2.6" | 3.8" | 0" | ✅ Rainfall sufficient |
| Mar | 2.6" | 2.2" | 0.4" | 💧 Light watering |
| Apr | 2.6" | 1.5" | 1.1" | 💧 Light watering |
| May | 2.6" | 0.5" | 2.1" | 🚿 Regular watering |
| Jun | 2.6" | 0.1" | 2.5" | 🚿 Regular watering |
| Jul | 2.6" | 0" | 2.6" | 🚿 Regular watering |
| Aug | 2.6" | 0" | 2.6" | 🚿 Regular watering |
| Sep | 2.6" | 0.2" | 2.4" | 🚿 Regular watering |
| Oct | 2.6" | 0.7" | 1.9" | 🚿 Regular watering |
| Nov | 2.6" | 1.7" | 0.9" | 💧 Light watering |
| Dec | — | 3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Feb–Nov in San Bernardino 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 Planting Timeline — San Bernardino County, CA
Basil Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 13 | Jan 13 – Jan 27 |
| Transplant Outdoors | March 3 | Mar 3 – Mar 17 |
| Direct Sow | March 3 | Mar 3 – Mar 24 |
| Harvest | April 28 | Apr 28 – Jun 30 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| February | — |
| March | Transplant Outdoors Direct Sow |
| April | Harvest |
| May | Harvest |
| June | Harvest |
| July | — |
| August | — |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.6"/week · 1-2 times/week
📅 Days to Maturity
50–75 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 9a
📆 Growing Season
274 days in San Bernardino County
Growing Tips for Basil in San Bernardino County
Direct sow Basil outdoors after February 24 in San Bernardino County when soil has warmed and frost danger has passed.
With summer highs reaching 97°F in San Bernardino County, provide afternoon shade for Basil and water deeply in the morning.
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
Check more plant combinations with our Companion Planting Checker →
Isolate 150 ft between varieties. Different basil species can cross.
Basil in Other Locations
Frequently Asked Questions
When should I plant Basil in San Bernardino County, CA?
San Bernardino County is in Zone 9a with an average last frost of February 24. Plan your Basil planting based on this frost date — see the calendar above for exact timing.
What planting zone is San Bernardino County, CA?
San Bernardino County, California is in USDA Hardiness Zone 9a. The average last spring frost is February 24 and first fall frost is November 25.
Plan Your Garden with Confidence
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