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When to Plant Lemongrass in Kern County, CA

Kern County, California Zone 9b May

Your May gardening checklist

Here's what deserves your attention in Kern County, California this month. Everything below is tailored to Zone 9b and timed around your local frost dates.

Avg. last frost February 28
Avg. first frost November 29
Soil temp (4") 78°F
Watering Critical
Pest pressure High
Daylight 13.9 hrs
  1. It's harvest week for lemongrass

    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.

Kern County, California is in USDA Zone 9b. The average last spring frost is February 28 and the first fall frost is November 29, giving you a growing season of approximately 274 days.

At an elevation of 389 feet, Kern County receives approximately 16.9 inches of rainfall annually with predominantly loam soil. Summer highs average 102°F, so Lemongrass may need afternoon shade and extra watering during peak heat. With low rainfall, drip irrigation is essential for growing Lemongrass successfully. Mulch heavily to conserve soil moisture.

Kern County, CA (Zone 9b) Year-round
274 days
Last Spring Frost February 28
274 growing days
First Fall Frost November 29

Kern County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (99 days to spare)
Start indoors: Jan 9 Transplant: Feb 27 🍅 Harvest: May 15 – Aug 14
Recommended (50%) ✓ Fits season (99 days to spare)
Start indoors: Jan 17 Transplant: Mar 7 🍅 Harvest: May 23 – Aug 22
Safe Start (90%) ✓ Fits season (81 days to spare)
Start indoors: Feb 24 Transplant: Apr 14 🍅 Harvest: Jun 30 – Sep 29

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 Kern County

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

Soil pH

Your soil pH (6.2–7.7) overlaps with Lemongrass's range (5.5–7.5), though not a perfect match.

Soil Texture

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

Drainage

Lemongrass is a heavy drinker but your soil drains very quickly. Mulch heavily and consider drip irrigation.

Organic Matter

Organic matter is moderate (2.3%). 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 274-day season

Sow every 8.6 weeks. Last sowing by Aug 01 to harvest before frost.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.3″/week
You supply
2.0″/week
Watering frequency 2-3 times/week
Season total 4,969 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 3.9" 0" ❄️ Dormant
Feb 6.5" 3.4" 3.1" 💧 Light watering
Mar 6.5" 2.4" 4.1" 🚿 Regular watering
Apr 6.5" 1.2" 5.3" 🚿 Regular watering
May 6.5" 0.5" 6" 🚿 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" 1.7" 4.8" 🚿 Regular watering
Dec 2.8" 0" ❄️ Dormant

Water needs are for active growing months only (Feb–Nov in Kern 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 ~2,584 GDD — county provides 7,287 GDD Excellent fit

Lemongrass Planting Timeline — Kern County, CA

Lemongrass Planting Calendar

Activity When Date Range
Start Indoors January 17 Jan 17 – Jan 31
Transplant Outdoors March 7 Mar 7 – Mar 21
Direct Sow March 7 Mar 7 – Mar 28
Harvest May 23 May 23 – Aug 22

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

Month-by-Month Timeline

MonthActivities
January Start Indoors
February
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 9b

📆 Growing Season

274 days in Kern County

Growing Tips for Lemongrass in Kern County

Direct sow Lemongrass outdoors after February 28 in Kern County when soil has warmed and frost danger has passed.

With summer highs reaching 102°F in Kern County, provide afternoon shade for Lemongrass and water deeply in the morning.

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

Kern 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 Kern County, CA?

Kern County is in Zone 9b with an average last frost of February 28. Plan your Lemongrass planting based on this frost date — see the calendar above for exact timing.

What planting zone is Kern County, CA?

Kern County, California is in USDA Hardiness Zone 9b. The average last spring frost is February 28 and first fall frost is November 29.

🌱

Your Kern County Garden Planner — Free

A 24-page printable planner built for Kern 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.

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 Kern 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.