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When to plant Celtuce in Pacifica, CA

Spring Celtuce in Pacifica goes in December 28–January 18, once nighttime temps stop dipping near freezing. A second sowing from October 17 to October 31 extends the harvest into fall.

When to Plant Celtuce in Pacifica, CA

San Mateo County, California Zone 10a June

June to-do list for San Mateo County, California

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

Avg. last frost January 18
Avg. first frost December 12
Soil temp (4") 85°F
Watering Critical
Pest pressure High
Daylight 14.6 hrs
  1. Survive, don't thrive

    June-August is endurance gardening. Keep okra, peppers, sweet potatoes, and southern peas alive. Harvest everything daily before the heat damages produce on the vine.

  2. Start fall tomato seeds indoors

    Yes, indoors — under lights or in AC. They'll be ready to transplant in August when temperatures briefly moderate.

  3. Add compost to empty beds

    Empty beds get a thick layer of compost + mulch to suppress weeds and feed the soil for fall planting.

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Celtuce (stem lettuce) is a Chinese vegetable grown for its thick, crunchy stem rather than its leaves. The peeled stem has a mild, cucumber-like flavor.

Pacifica, California is in USDA Zone 10a. The average last spring frost is January 18 and the first fall frost is December 12, giving you a growing season of approximately 328 days.

At an elevation of 277 feet, San Mateo County receives approximately 16.9 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Celtuce to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Celtuce successfully. Mulch heavily to conserve soil moisture.

Pacifica, CA (Zone 10a) Year-round
328 days
Last Spring Frost January 18
328 growing days
First Fall Frost December 12

Pacifica Soil Profile

Soil Type

Loam

Soil pH

6.8-7.2

Drainage

Well Drained

Celtuce Planting Risk Windows

Early Start (70% safe) ✓ Fits season (220 days to spare)
Start indoors: Dec 17 Transplant: Jan 14 🍅 Harvest: Mar 18 – Apr 29
Recommended (50%) ✓ Fits season (223 days to spare)
Start indoors: Dec 21 Transplant: Jan 18 🍅 Harvest: Mar 22 – May 3
Safe Start (90%) ✓ Fits season (170 days to spare)
Start indoors: Feb 24 Transplant: Mar 24 🍅 Harvest: May 26 – Jul 7

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 Pacifica

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

Soil pH

Your soil pH (6.8–7.2) overlaps with Celtuce's range (6.0–7.0), though not a perfect match.

Soil Texture

The loam soil in San Mateo County is excellent for Celtuce — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Celtuce.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Celtuce.

How to Plant Celtuce

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 Celtuce

6
successive plantings in your 328-day season

Sow every 6.9 weeks. Last sowing by Sep 13 to harvest before frost.

For a dedicated fall crop, sow by Oct 17.

Celtuce Water Budget

Plant needs
0.7″/week
Rainfall provides
0.2″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 2,439 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Celtuce

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

Month Celtuce Needs Rainfall You Supplement Action
Jan 3" 3.9" 0" ✅ Rainfall sufficient
Feb 3" 3.4" 0" ✅ Rainfall sufficient
Mar 3" 2.7" 0.3" 💧 Light watering
Apr 3" 1.2" 1.8" 🚿 Regular watering
May 3" 0.4" 2.6" 🚿 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" 1.4" 1.6" 🚿 Regular watering
Dec 3" 2.9" 0.1" 💧 Light watering

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

Celtuce 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.

Celtuce needs ~806 GDD — county provides 3,536 GDD Excellent fit

Celtuce Planting Timeline — Pacifica, CA

Celtuce Planting Calendar

Activity When Date Range
Start Indoors December 21 Dec 21 – Jan 4
Transplant Outdoors January 18 Jan 18 – Feb 1
Direct Sow December 28 Dec 28 – Jan 18
Harvest March 22 Mar 22 – May 3
Fall Sowing October 17 Oct 17 – Oct 31

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.7"/week · 2-3 times/week

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 10a

📆 Growing Season

328 days in San Mateo County

Growing Tips for Celtuce in Pacifica

Direct sow Celtuce outdoors after January 18 in San Mateo County when soil has warmed and frost danger has passed.

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

General growing tips

Direct sow in spring or start indoors. Space 12 inches apart. Harvest when stems are about 1 inch in diameter. Peel the tough outer skin to reveal the tender center.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

When should I plant Celtuce in Pacifica, CA?

In Pacifica, CA, plant Celtuce after the last frost (around January 18) and before the first frost (around December 12). Best results when soil holds above 50°F.

What growing zone is Pacifica, CA for Celtuce?

Pacifica sits in USDA Zone 10a. Celtuce grows reliably in zones 3a through 10b, so it's a good fit here.

Can Celtuce grow in Pacifica's climate?

Yes — Celtuce grows well in Pacifica's temperate climate. Pacifica averages a 329-day frost-free season, with last frost around January 18 and first frost around December 12.

🌱

Your San Mateo County Garden Planner — Free

A 22-page printable planner built for San Mateo 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 San Mateo County, CA. Local conditions may vary. Last updated: June 2026.