Blog

When to Plant Celtuce in Modoc 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.

Modoc County, California is in USDA Zone 6a. The average last spring frost is May 31 and the first fall frost is September 21, giving you a growing season of approximately 113 days.

At an elevation of 2,205 feet, Modoc County receives approximately 28.3 inches of rainfall annually with predominantly loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Celtuce to ensure they mature before fall.

Modoc County, CA (Zone 6a) Short season
113 days
Last Spring Frost May 31
113 growing days
First Fall Frost September 21

Modoc County Soil Profile

Soil Type

Loam

Soil pH

5.9-7.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (15 days to spare)
Start indoors: Apr 14 Transplant: May 19 🍅 Harvest: Jul 21 – Sep 1
Recommended (50%) ✓ Fits season (8 days to spare)
Start indoors: Apr 26 Transplant: May 31 🍅 Harvest: Aug 2 – Sep 13
Safe Start (90%) ✓ Fits season (14 days to spare)
Start indoors: May 15 Transplant: Jun 19 🍅 Harvest: Aug 21 – Oct 2

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 Modoc County

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

Soil pH

Your soil pH (5.9โ€“7.4) overlaps with Celtuce's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

The loam soil in Modoc 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 (2.1%). Annual compost additions will help Celtuce.

How to Plant Celtuce

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

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Celtuce

2
successive plantings in your 113-day season

Sow every 6.9 weeks. Last sowing by Jun 23 to harvest before frost.

For a dedicated fall crop, sow by Jul 13.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 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€” 5.6" 0" โ„๏ธ Dormant
Feb โ€” 5.8" 0" โ„๏ธ Dormant
Mar โ€” 4.1" 0" โ„๏ธ Dormant
Apr โ€” 2.1" 0" โ„๏ธ Dormant
May 3" 0.7" 2.3" ๐Ÿšฟ Regular watering
Jun 3" 0.1" 2.9" 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 โ€” 1.3" 0" โ„๏ธ Dormant
Nov โ€” 2.7" 0" โ„๏ธ Dormant
Dec โ€” 5.5" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Modoc 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 ~919 GDD — county provides 1,384 GDD Excellent fit

Celtuce Planting Timeline โ€” Modoc County, CA

Celtuce Planting Calendar

Activity When Date Range
Start Indoors April 26 Apr 26 โ€“ May 10
Transplant Outdoors May 31 May 31 โ€“ Jun 14
Direct Sow May 17 May 17 โ€“ Jun 7
Harvest August 2 Aug 2 โ€“ Sep 13
Fall Sowing July 13 Jul 13 โ€“ Jul 27

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.7"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

60โ€“90 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 6a

๐Ÿ“† Growing Season

113 days in Modoc County

Growing Tips for Celtuce in Modoc County

Direct sow Celtuce outdoors after May 31 in Modoc 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 Modoc County, CA?

Modoc County is in Zone 6a with an average last frost of May 31. Plan your Celtuce planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Modoc County, CA?

Modoc County, California is in USDA Hardiness Zone 6a. The average last spring frost is May 31 and first fall frost is September 21.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Modoc County gardeners in Zone 6a 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 Modoc County, CA. Local conditions may vary. Last updated: April 2026.