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When to Plant Lettuce in Kern County, CA

Kern County, California Zone 9b May

This month in Kern County, California

Each item below is timed to Kern County, California's frost dates and soil temperatures. Skip nothing, stress about nothing.

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. Harvest lettuce as they ripen

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

June will be here before you know it — start on
  • First harvests: lettuce

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Lettuce is a fast-growing cool-season green available in leaf, romaine, butterhead, and crisphead types. It is the foundation of salads and one of the easiest crops to grow.

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 Lettuce may need afternoon shade and extra watering during peak heat. With low rainfall, drip irrigation is essential for growing Lettuce 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 (169 days to spare)
Start indoors: Jan 23 Transplant: Feb 20 🍅 Harvest: Mar 27 – Jun 5
Recommended (50%) ✓ Fits season (169 days to spare)
Start indoors: Jan 31 Transplant: Feb 28 🍅 Harvest: Apr 4 – Jun 13
Safe Start (90%) ✓ Fits season (151 days to spare)
Start indoors: Mar 10 Transplant: Apr 7 🍅 Harvest: May 12 – Jul 21

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 Lettuce's growing requirements.

Soil pH

Your soil pH (6.2–7.7) overlaps with Lettuce's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Lettuce.

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Lettuce.

How to Plant Lettuce

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Succession Planting Lettuce

11
successive plantings in your 274-day season

Sow every 3.4 weeks. Last sowing by Sep 30 to harvest before frost.

For a dedicated fall crop, sow by Oct 04.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.3″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 1,915 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Lettuce

Lettuce needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Lettuce Needs Rainfall You Supplement Action
Jan 3.9" 0" ❄️ Dormant
Feb 3" 3.4" 0" ✅ Rainfall sufficient
Mar 3" 2.4" 0.6" 💧 Light watering
Apr 3" 1.2" 1.8" 🚿 Regular watering
May 3" 0.5" 2.5" 🚿 Regular watering
Jun 3" 0.1" 2.9" 🚿 Regular watering
Jul 3" 0" 3" 🚿 Regular watering
Aug 3" 0" 3" 🚿 Regular watering
Sep 3" 0.2" 2.8" 🚿 Regular watering
Oct 3" 0.7" 2.3" 🚿 Regular watering
Nov 3" 1.7" 1.3" 💧 Light 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.

Lettuce 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.

Lettuce needs ~1,192 GDD — county provides 7,287 GDD Excellent fit

Lettuce Planting Timeline — Kern County, CA

Lettuce Planting Calendar

Activity When Date Range
Start Indoors January 31 Jan 31 – Feb 14
Transplant Outdoors February 28 Feb 28 – Mar 14
Direct Sow February 7 Feb 7 – Feb 28
Harvest April 4 Apr 4 – Jun 13
Fall Sowing October 4 Oct 4 – Oct 18

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.7"/week · 2-3 times/week

📅 Days to Maturity

30–60 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 9b

📆 Growing Season

274 days in Kern County

Growing Tips for Lettuce in Kern County

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

Summer highs in Kern County reach 102°F — grow Lettuce as a spring or fall crop. Use shade cloth if planting in summer.

Your generous 275.0-day season in Kern County allows multiple plantings of Lettuce. Sow every 15.0 days for continuous harvest.

Common pests for Lettuce in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Sow seeds directly every 2 weeks for continuous harvest. Provide afternoon shade in warm weather to delay bolting. Harvest in the morning for crispest leaves.

Recommended Lettuce Varieties for Kern County

Bolt-resistant varieties for warm summers — grow as spring/fall crop

Jericho Muir Nevada New Red Fire

Companion Planting

Good Companions

Avoid Planting Near

  • Celery

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Lettuce Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Let plants bolt and flower. Harvest seed heads when fluffy.
Storage Store airtight; viable 6 years at 35°F, under 45% humidity.

Very easy to save. Let a few plants bolt each season.

Frequently Asked Questions

When should I plant Lettuce in Kern County, CA?

Kern County is in Zone 9b with an average last frost of February 28. Plan your Lettuce 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.

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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 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.