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When to Plant Celtuce in Solano County, CA

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.

Solano County, California is in USDA Zone 9a. The average last spring frost is February 9 and the first fall frost is December 3, giving you a growing season of approximately 297 days.

At an elevation of 376 feet, Solano County receives approximately 40.4 inches of rainfall annually with predominantly loam soil. Summer highs average 95ยฐF, so Celtuce may need afternoon shade and extra watering during peak heat.

Solano County, CA (Zone 9a) Year-round
297 days
Last Spring Frost February 9
297 growing days
First Fall Frost December 3

Solano County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (200 days to spare)
Start indoors: Dec 28 Transplant: Jan 25 🍅 Harvest: Mar 29 – May 10
Recommended (50%) ✓ Fits season (192 days to spare)
Start indoors: Jan 12 Transplant: Feb 9 🍅 Harvest: Apr 13 – May 25
Safe Start (90%) ✓ Fits season (176 days to spare)
Start indoors: Feb 13 Transplant: Mar 13 🍅 Harvest: May 15 – Jun 26

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 Solano County

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

Soil pH

Your soil pH (6.8โ€“7.3) is more alkaline than Celtuce prefers (6.0โ€“7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Solano County is excellent for Celtuce โ€” 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

5
successive plantings in your 297-day season

Sow every 6.9 weeks. Last sowing by Sep 04 to harvest before frost.

For a dedicated fall crop, sow by Oct 08.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.6″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 1,084 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” 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 โ€” 8.9" 0" โ„๏ธ Dormant
Feb 3" 8.4" 0" โœ… Rainfall sufficient
Mar 3" 6.6" 0" โœ… Rainfall sufficient
Apr 3" 2.7" 0.3" ๐Ÿ’ง Light watering
May 3" 1" 2" ๐Ÿšฟ Regular watering
Jun 3" 0.2" 2.8" ๐Ÿšฟ Regular watering
Jul 3" 0" 3" ๐Ÿšฟ Regular watering
Aug 3" 0" 3" ๐Ÿšฟ Regular watering
Sep 3" 0.4" 2.6" ๐Ÿšฟ Regular watering
Oct 3" 1.9" 1.1" ๐Ÿ’ง Light watering
Nov 3" 3.3" 0" โœ… Rainfall sufficient
Dec 3" 7.1" 0" โœ… Rainfall sufficient

Water needs are for active growing months only (Febโ€“Dec in Solano County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~1,594 GDD — county provides 6,332 GDD Excellent fit

Celtuce Planting Timeline โ€” Solano County, CA

Celtuce Planting Calendar

Activity When Date Range
Start Indoors January 12 Jan 12 โ€“ Jan 26
Transplant Outdoors February 9 Feb 9 โ€“ Feb 23
Direct Sow January 19 Jan 19 โ€“ Feb 9
Harvest April 13 Apr 13 โ€“ May 25
Fall Sowing October 8 Oct 8 โ€“ Oct 22

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.7"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

60โ€“90 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 9a

๐Ÿ“† Growing Season

297 days in Solano County

Growing Tips for Celtuce in Solano County

Direct sow Celtuce outdoors after February 09 in Solano 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 →

Frequently Asked Questions

When should I plant Celtuce in Solano County, CA?

Solano County is in Zone 9a with an average last frost of February 9. Plan your Celtuce planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Solano County, CA?

Solano County, California is in USDA Hardiness Zone 9a. The average last spring frost is February 9 and first fall frost is December 3.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Solano County gardeners in Zone 9a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Solano County, CA. Local conditions may vary. Last updated: April 2026.