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When to Plant Tomatoes in Lassen County, CA

Tomatoes are the most popular home garden crop, available in thousands of varieties from tiny cherries to massive beefsteaks. They are warm-season plants needing full sun.

Lassen County, California is in USDA Zone 6b. The average last spring frost is May 28 and the first fall frost is September 29, giving you a growing season of approximately 124 days.

At an elevation of 1,854 feet, Lassen County receives approximately 43.7 inches of rainfall annually with predominantly loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Tomatoes to ensure they mature before fall.

Lassen County, CA (Zone 6b) Short season
124 days
Last Spring Frost May 28
124 growing days
First Fall Frost September 29

Lassen County Soil Profile

Soil Type

Loam

Soil pH

6.1-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 23 Transplant: Jun 1 🍅 Harvest: Aug 3 – Oct 12
Recommended (50%) ✗ May not fit
Start indoors: Apr 2 Transplant: Jun 11 🍅 Harvest: Aug 13 – Oct 22
Safe Start (90%) ✗ May not fit
Start indoors: Apr 24 Transplant: Jul 3 🍅 Harvest: Sep 4 – Nov 13

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 Lassen County

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

Soil pH

Your soil pH (6.1โ€“7.5) overlaps with Tomatoes's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

The loam soil in Lassen County is excellent for Tomatoes โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

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

How to Plant Tomatoes

0.5"
Planting Depth
24"
Between Plants
36"
Between Rows

Succession Planting Tomatoes

2
successive plantings in your 124-day season

Sow every 6.9 weeks. Last sowing by Jul 06 to harvest before frost.

Plant Water Budget

Plant needs
1.2″/week
Rainfall provides
1.5″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Monthly Watering Guide for Tomatoes

Tomatoes needs approximately 1.2 inches of water per week (5.2" per month). Here's how your county's rainfall compares month by month.

Month Tomatoes Needs Rainfall You Supplement Action
Jan โ€” 9.2" 0" โ„๏ธ Dormant
Feb โ€” 9.8" 0" โ„๏ธ Dormant
Mar โ€” 7.7" 0" โ„๏ธ Dormant
Apr โ€” 3.2" 0" โ„๏ธ Dormant
May 5.2" 1" 4.2" ๐Ÿšฟ Regular watering
Jun 5.2" 0.2" 5" ๐Ÿšฟ Regular watering
Jul 5.2" 0" 5.2" ๐Ÿšฟ Regular watering
Aug 5.2" 0" 5.2" ๐Ÿšฟ Regular watering
Sep 5.2" 0.5" 4.7" ๐Ÿšฟ Regular watering
Oct โ€” 1.7" 0" โ„๏ธ Dormant
Nov โ€” 3.9" 0" โ„๏ธ Dormant
Dec โ€” 6.5" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Lassen County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Tomatoes 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.

Tomatoes needs ~942 GDD — county provides 1,612 GDD Excellent fit

Tomatoes Planting Timeline โ€” Lassen County, CA

Tomatoes Planting Calendar

Activity When Date Range
Start Indoors April 2 Apr 2 โ€“ Apr 16
Transplant Outdoors June 11 Jun 11 โ€“ Jun 25
Direct Sow June 4 Jun 4 โ€“ Jun 25
Harvest August 13 Aug 13 โ€“ Oct 22

Plant 0.5" deep ยท 24" apart ยท Rows 36" apart

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1.2"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

60โ€“85 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 6b

๐Ÿ“† Growing Season

124 days in Lassen County

Growing Tips for Tomatoes in Lassen County

Direct sow Tomatoes outdoors after May 28 in Lassen County when soil has warmed and frost danger has passed.

Common pests for Tomatoes in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 6-8 weeks before last frost. Bury transplants deep to encourage rooting along the stem. Provide consistent moisture to prevent blossom end rot and cracking.

Recommended Tomatoes Varieties for Lassen County

Choose determinate, early-maturing varieties for your short season

Early Girl (52d) Stupice (55d) Glacier (55d) Sub Arctic Plenty (45d)

Companion Planting

Good Companions

Avoid Planting Near

  • Cabbage
  • Fennel
  • Potatoes

Check more plant combinations with our Companion Planting Checker →

๐ŸŒพ Save Your Own Tomatoes Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Scoop seeds from ripe fruit; ferment 2-3 days to remove gel coating.
Storage Store airtight; viable 4-6 years at 35ยฐF, under 45% humidity.

Isolate 25 ft between varieties for purity. Use open-pollinated varieties for true-to-type seeds.

Frequently Asked Questions

When should I plant Tomatoes in Lassen County, CA?

Lassen County is in Zone 6b with an average last frost of May 28. Plan your Tomatoes planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Lassen County, CA?

Lassen County, California is in USDA Hardiness Zone 6b. The average last spring frost is May 28 and first fall frost is September 29.

๐ŸŒฑ

Plan Your Garden with Confidence

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