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When to Plant Lemongrass in Orange County, CA

Orange County, California Zone 10b May

May in Orange County, California — your action list

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost February 13
Avg. first frost December 11
Soil temp (4") 79°F
Watering Critical
Pest pressure High
Daylight 13.7 hrs
  1. Collect lemongrass at their peak

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

Looking ahead to June
  • First harvests: lemongrass

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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.

Orange County, California is in USDA Zone 10b. The average last spring frost is February 13 and the first fall frost is December 11, giving you a growing season of approximately 301 days.

At an elevation of 405 feet, Orange County receives approximately 13.8 inches of rainfall annually with predominantly loam soil. Summer highs average 88°F, 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.

Orange County, CA (Zone 10b) Year-round
301 days
Last Spring Frost February 13
301 growing days
First Fall Frost December 11

Orange County Soil Profile

Soil Type

Loam

Soil pH

5.7-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (125 days to spare)
Start indoors: Dec 22 Transplant: Feb 9 🍅 Harvest: Apr 27 – Jul 27
Recommended (50%) ✓ Fits season (126 days to spare)
Start indoors: Jan 2 Transplant: Feb 20 🍅 Harvest: May 8 – Aug 7
Safe Start (90%) ✓ Fits season (87 days to spare)
Start indoors: Feb 19 Transplant: Apr 9 🍅 Harvest: Jun 25 – Sep 24

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 Orange County

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

Soil pH

Your soil pH (5.7–7.6) overlaps with Lemongrass's range (5.5–7.5), though not a perfect match.

Soil Texture

The loam soil in Orange County is excellent for Lemongrass — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.1%). Annual compost additions will help Lemongrass.

How to Plant Lemongrass

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

Succession Planting Lemongrass

4
successive plantings in your 301-day season

Sow every 8.6 weeks. Last sowing by Aug 13 to harvest before frost.

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 4,219 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Lemongrass

Lemongrass needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Lemongrass Needs Rainfall You Supplement Action
Jan 2.4" 0" ❄️ Dormant
Feb 6.5" 2.6" 3.9" 🚿 Regular watering
Mar 6.5" 2.2" 4.3" 🚿 Regular watering
Apr 6.5" 1.1" 5.4" 🚿 Regular watering
May 6.5" 0.4" 6.1" 🚿 Regular watering
Jun 6.5" 0.1" 6.4" 🚿 Regular watering
Jul 6.5" 0" 6.5" 🚿 Regular watering
Aug 6.5" 0" 6.5" 🚿 Regular watering
Sep 6.5" 0.2" 6.3" 🚿 Regular watering
Oct 6.5" 0.7" 5.8" 🚿 Regular watering
Nov 6.5" 1.5" 5" 🚿 Regular watering
Dec 6.5" 2.7" 3.8" 🚿 Regular watering

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

Lemongrass 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.

Lemongrass needs ~1,560 GDD — county provides 4,832 GDD Excellent fit

Lemongrass Planting Timeline — Orange County, CA

Lemongrass Planting Calendar

Activity When Date Range
Start Indoors January 2 Jan 2 – Jan 16
Transplant Outdoors February 20 Feb 20 – Mar 6
Direct Sow February 20 Feb 20 – Mar 13
Harvest May 8 May 8 – Aug 7

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.5"/week · 2-3 times/week

📅 Days to Maturity

75–120 days

🧪 Soil pH

Needs 5.5–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 10b

📆 Growing Season

301 days in Orange County

Growing Tips for Lemongrass in Orange County

Direct sow Lemongrass outdoors after February 13 in Orange County when soil has warmed and frost danger has passed.

Common pests for Lemongrass in this region include corn earworm and corn borers. Use row covers early in the season and inspect plants weekly.

Orange County receives only 14" of rain annually. Lemongrass needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Lemongrass in Orange County, CA?

Orange County is in Zone 10b with an average last frost of February 13. Plan your Lemongrass planting based on this frost date — see the calendar above for exact timing.

What planting zone is Orange County, CA?

Orange County, California is in USDA Hardiness Zone 10b. The average last spring frost is February 13 and first fall frost is December 11.

🌱

Your Orange County Garden Planner — Free

A 24-page printable planner built for Orange County (Zone 10b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Orange County, CA. 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.