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When to Plant Mizuna in Lassen County, CA

Mizuna is a mild-flavored Japanese mustard green with feathery, deeply serrated leaves. It is fast-growing and makes an excellent addition to salads and stir-fries.

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 Mizuna 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) ✓ Fits season (59 days to spare)
Start indoors: Apr 13 Transplant: May 18 🍅 Harvest: Jun 22 – Jul 20
Recommended (50%) ✓ Fits season (61 days to spare)
Start indoors: Apr 23 Transplant: May 28 🍅 Harvest: Jul 2 – Jul 30
Safe Start (90%) ✓ Fits season (65 days to spare)
Start indoors: May 15 Transplant: Jun 19 🍅 Harvest: Jul 24 – Aug 21

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 Mizuna's growing requirements.

Soil pH

Your soil pH (6.1โ€“7.5) is within Mizuna's preferred range (6.0โ€“7.5).

Soil Texture

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

Organic Matter

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

How to Plant Mizuna

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 Mizuna

4
successive plantings in your 124-day season

Sow every 3.4 weeks. Last sowing by Aug 15 to harvest before frost.

For a dedicated fall crop, sow by Jul 21.

Plant Water Budget

Plant needs
1.0″/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 Mizuna

Mizuna needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Mizuna 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 4.3" 1" 3.3" ๐Ÿšฟ Regular watering
Jun 4.3" 0.2" 4.1" ๐Ÿšฟ Regular watering
Jul 4.3" 0" 4.3" ๐Ÿšฟ Regular watering
Aug 4.3" 0" 4.3" ๐Ÿšฟ Regular watering
Sep 4.3" 0.5" 3.8" 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.

Mizuna 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.

Mizuna needs ~488 GDD — county provides 1,612 GDD Excellent fit

Mizuna Planting Timeline โ€” Lassen County, CA

Mizuna Planting Calendar

Activity When Date Range
Start Indoors April 23 Apr 23 โ€“ May 7
Transplant Outdoors May 28 May 28 โ€“ Jun 11
Direct Sow May 14 May 14 โ€“ Jun 4
Harvest July 2 Jul 2 โ€“ Jul 30
Fall Sowing July 21 Jul 21 โ€“ Aug 4

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 Harvest
August Fall Sowing
September โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Partial Shade (3-6 hours)

๐Ÿ’ง Water

1"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

30โ€“45 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 6b

๐Ÿ“† Growing Season

124 days in Lassen County

Growing Tips for Mizuna in Lassen County

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

Your generous 124.0-day season in Lassen County allows multiple plantings of Mizuna. Sow every 15.0 days for continuous harvest.

Common pests for Mizuna in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow in spring or fall. Harvest outer leaves as needed for a cut-and-come-again approach. Mizuna is one of the most cold-tolerant Asian greens.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Mizuna in Lassen County, CA?

Lassen County is in Zone 6b with an average last frost of May 28. Plan your Mizuna 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.

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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 Lassen County, CA. Local conditions may vary. Last updated: April 2026.