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When to Plant Lettuce in Monterey County, CA

Monterey County, California Zone 9b May

Monterey County, California gardeners: here's your May plan

Your garden in Monterey County, California is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost March 13
Avg. first frost November 17
Soil temp (4") 76°F
Watering Critical
Pest pressure High
Daylight 13.9 hrs
  1. It's harvest week for lettuce

    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: 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.

Monterey County, California is in USDA Zone 9b. The average last spring frost is March 13 and the first fall frost is November 17, giving you a growing season of approximately 249 days.

At an elevation of 260 feet, Monterey County receives approximately 12.5 inches of rainfall annually with predominantly loam soil. Summer highs average 93°F, providing good warmth for Lettuce during the growing season. With low rainfall, drip irrigation is essential for growing Lettuce successfully. Mulch heavily to conserve soil moisture.

Monterey County, CA (Zone 9b) Long season
249 days
Last Spring Frost March 13
249 growing days
First Fall Frost November 17
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Monterey County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (143 days to spare)
Start indoors: Jan 30 Transplant: Feb 27 🍅 Harvest: Apr 3 – Jun 12
Recommended (50%) ✓ Fits season (144 days to spare)
Start indoors: Feb 13 Transplant: Mar 13 🍅 Harvest: Apr 17 – Jun 26
Safe Start (90%) ✓ Fits season (109 days to spare)
Start indoors: Apr 19 Transplant: May 17 🍅 Harvest: Jun 21 – Aug 30

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 Monterey County

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

Soil pH

Your soil pH (6.7–7.2) overlaps with Lettuce's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.7%). 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

10
successive plantings in your 249-day season

Sow every 3.4 weeks. Last sowing by Sep 18 to harvest before frost.

For a dedicated fall crop, sow by Sep 22.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.2″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 1,301 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 2.7" 0" ❄️ Dormant
Feb 2.6" 0" ❄️ Dormant
Mar 3" 2.1" 0.9" 💧 Light watering
Apr 3" 1" 2" 🚿 Regular watering
May 3" 0.3" 2.7" 🚿 Regular watering
Jun 3" 0.1" 2.9" 🚿 Regular watering
Jul 3" 0" 3" 🚿 Regular watering
Aug 3" 0" 3" 🚿 Regular watering
Sep 3" 0.1" 2.9" 🚿 Regular watering
Oct 3" 0.5" 2.5" 🚿 Regular watering
Nov 3" 1.2" 1.8" 🚿 Regular watering
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Monterey 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 ~889 GDD — county provides 4,917 GDD Excellent fit

Lettuce Planting Timeline — Monterey County, CA

Lettuce Planting Calendar

Activity When Date Range
Start Indoors February 13 Feb 13 – Feb 27
Transplant Outdoors March 13 Mar 13 – Mar 27
Direct Sow February 20 Feb 20 – Mar 13
Harvest April 17 Apr 17 – Jun 26
Fall Sowing September 22 Sep 22 – Oct 6

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

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.7"/week · 1-2 times/week

📅 Days to Maturity

30–60 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 9b

📆 Growing Season

249 days in Monterey County

Growing Tips for Lettuce in Monterey County

Direct sow Lettuce outdoors after March 13 in Monterey County when soil has warmed and frost danger has passed.

Summer highs in Monterey County reach 93°F — grow Lettuce as a spring or fall crop. Use shade cloth if planting in summer.

Your generous 249.0-day season in Monterey 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 Monterey 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 Monterey County, CA?

Monterey County is in Zone 9b with an average last frost of March 13. Plan your Lettuce planting based on this frost date — see the calendar above for exact timing.

What planting zone is Monterey County, CA?

Monterey County, California is in USDA Hardiness Zone 9b. The average last spring frost is March 13 and first fall frost is November 17.

🌱

Your Monterey County Garden Planner — Free

A 24-page printable planner built for Monterey 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 Monterey 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.