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When to Plant Lemongrass in San Joaquin County, CA

Lemongrass is a tropical grass with a strong citrus aroma used extensively in Southeast Asian cuisine. The swollen stem bases are the most flavorful part.

San Joaquin County, California is in USDA Zone 9a. The average last spring frost is February 4 and the first fall frost is December 6, giving you a growing season of approximately 305 days.

At an elevation of 220 feet, San Joaquin County receives approximately 15 inches of rainfall annually with predominantly loam soil. Summer highs average 93ยฐF, providing good warmth for Lemongrass during the growing season. With low rainfall, drip irrigation is essential for growing Lemongrass successfully. Mulch heavily to conserve soil moisture.

San Joaquin County, CA (Zone 9a) Year-round
305 days
Last Spring Frost February 4
305 growing days
First Fall Frost December 6

San Joaquin County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (140 days to spare)
Start indoors: Dec 7 Transplant: Jan 25 🍅 Harvest: Apr 12 – Jul 12
Recommended (50%) ✓ Fits season (130 days to spare)
Start indoors: Dec 24 Transplant: Feb 11 🍅 Harvest: Apr 29 – Jul 29
Safe Start (90%) ✓ Fits season (114 days to spare)
Start indoors: Jan 22 Transplant: Mar 12 🍅 Harvest: May 28 – Aug 27

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.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.2″/week
You supply
1.6″/week
Watering frequency 2-3 times/week
Season total 4,229 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” consider drought-tolerant varieties and mulching

Lemongrass needs ~1,926 GDD — county provides 6,043 GDD Excellent fit

Lemongrass Planting Timeline โ€” San Joaquin County, CA

Lemongrass Planting Calendar

Activity When Date Range
Start Indoors December 24 Dec 24 โ€“ Jan 7
Transplant Outdoors February 11 Feb 11 โ€“ Feb 25
Direct Sow February 11 Feb 11 โ€“ Mar 4
Harvest April 29 Apr 29 โ€“ Jul 29

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

High โ€” keep soil consistently moist

Days to Maturity

75โ€“120 days

Soil pH

5.5 โ€“ 7.5

USDA Zone

Zone 9a

Growing Season

305 days

Growing Tips for San Joaquin County

Start from divisions or store-bought stalks rooted in water. Grow in rich, moist soil with full sun. In cold climates, grow in containers and overwinter indoors.

Companion Planting

Good Companions

Level Up Your Garden

Frequently Asked Questions

When should I plant Lemongrass in San Joaquin County, CA?

San Joaquin County is in Zone 9a with an average last frost of February 4. Plan your Lemongrass planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is San Joaquin County, CA?

San Joaquin County, California is in USDA Hardiness Zone 9a. The average last spring frost is February 4 and first fall frost is December 6.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help San Joaquin County gardeners in Zone 9a organize planting dates, track what's growing, and never miss a planting window.

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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 San Joaquin County, CA. Local conditions may vary. Last updated: April 2026.