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When to Plant Lemongrass in Imperial County, CA

Imperial County, California Zone 10a May

May to-do list for Imperial County, California

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 January 29
Avg. first frost December 20
Soil temp (4") 78°F
Watering Critical
Pest pressure High
Daylight 13.7 hrs
  1. Pick lemongrass

    If you can't use it all right away, check the food-preservation section of your planner.

To set up a strong June, finish these tasks
  • 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.

Imperial County, California is in USDA Zone 10a. The average last spring frost is January 29 and the first fall frost is December 20, giving you a growing season of approximately 325 days.

At an elevation of 181 feet, Imperial County receives approximately 16.8 inches of rainfall annually with predominantly loam soil. Summer highs average 93°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.

Imperial County, CA (Zone 10a) Year-round
325 days
Last Spring Frost January 29
325 growing days
First Fall Frost December 20
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Imperial County Soil Profile

Soil Type

Loam

Soil pH

5.7-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (158 days to spare)
Start indoors: Dec 5 Transplant: Jan 23 🍅 Harvest: Apr 10 – Jul 10
Recommended (50%) ✓ Fits season (150 days to spare)
Start indoors: Dec 18 Transplant: Feb 5 🍅 Harvest: Apr 23 – Jul 23
Safe Start (90%) ✓ Fits season (141 days to spare)
Start indoors: Jan 3 Transplant: Feb 21 🍅 Harvest: May 9 – Aug 8

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 Imperial County

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

Soil pH

Your soil pH (5.7–7.3) is within Lemongrass's preferred range (5.5–7.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Lemongrass.

How to Plant Lemongrass

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

Succession Planting Lemongrass

5
successive plantings in your 325-day season

Sow every 8.6 weeks. Last sowing by Aug 22 to harvest before frost.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.2″/week
You supply
1.5″/week
Watering frequency 2-3 times/week
Season total 4,469 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 6.5" 3" 3.5" 🚿 Regular watering
Feb 6.5" 3.3" 3.2" 💧 Light watering
Mar 6.5" 3.1" 3.4" 🚿 Regular watering
Apr 6.5" 1.4" 5.1" 🚿 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" 0.6" 5.9" 🚿 Regular watering
Nov 6.5" 1.5" 5" 🚿 Regular watering
Dec 6.5" 3.3" 3.2" 💧 Light watering

Water needs are for active growing months only (Jan–Dec in Imperial 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 ~1,926 GDD — county provides 6,438 GDD Excellent fit

Lemongrass Planting Timeline — Imperial County, CA

Lemongrass Planting Calendar

Activity When Date Range
Start Indoors December 18 Dec 18 – Jan 1
Transplant Outdoors February 5 Feb 5 – Feb 19
Direct Sow February 5 Feb 5 – Feb 26
Harvest April 23 Apr 23 – Jul 23

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 10a

📆 Growing Season

325 days in Imperial County

Growing Tips for Lemongrass in Imperial County

Direct sow Lemongrass outdoors after January 29 in Imperial 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.

Imperial County receives only 17" 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 Imperial County, CA?

Imperial County is in Zone 10a with an average last frost of January 29. Plan your Lemongrass planting based on this frost date — see the calendar above for exact timing.

What planting zone is Imperial County, CA?

Imperial County, California is in USDA Hardiness Zone 10a. The average last spring frost is January 29 and first fall frost is December 20.

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Your Imperial County Garden Planner — Free

A 24-page printable planner built for Imperial County (Zone 10a). 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 Imperial 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.