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When to Plant Mizuna in Cascade County, MT

Cascade County, Montana Zone 4b May

This month in Cascade County, Montana

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 19
Avg. first frost September 21
Soil temp (4") 33°F
Watering High
Pest pressure Low
Daylight 14.9 hrs
  1. Transplant mizuna outside

    Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.

  2. Sow mizuna where they'll grow

    Succession planting is the secret here. Put in a row now, another in 2 weeks, a third in 4.

Get ahead of June
  • Starting indoors: mizuna
  • First harvests: mizuna
  • Fall sowing: mizuna

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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.

Cascade County, Montana is in USDA Zone 4b. The average last spring frost is May 19 and the first fall frost is September 21, giving you a growing season of approximately 125 days.

At an elevation of 6,585 feet, Cascade County receives approximately 21.8 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Mizuna to ensure they mature before fall.

Cascade County, MT (Zone 4b) Short season
125 days
Last Spring Frost May 19
125 growing days
First Fall Frost September 21

Cascade County Soil Profile

Soil Type

Loam

Soil pH

6.8-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (61 days to spare)
Start indoors: Mar 31 Transplant: May 12 🍅 Harvest: Jun 16 – Jul 14
Recommended (50%) ✓ Fits season (62 days to spare)
Start indoors: Apr 7 Transplant: May 19 🍅 Harvest: Jun 23 – Jul 21
Safe Start (90%) ✓ Fits season (52 days to spare)
Start indoors: May 1 Transplant: Jun 12 🍅 Harvest: Jul 17 – Aug 14

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 Cascade County

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

Soil pH

Your soil pH (6.8–8.2) overlaps with Mizuna's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in Cascade County is excellent for Mizuna — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Mizuna.

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Mizuna.

How to Plant Mizuna

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

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Succession Planting Mizuna

4
successive plantings in your 125-day season

Sow every 3.4 weeks. Last sowing by Aug 07 to harvest before frost.

For a dedicated fall crop, sow by Jun 29.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.7″/week
Watering frequency 1-2 times/week
Season total 758 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 1.8" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2" 0" ❄️ Dormant
May 4.3" 2.3" 2" 💧 Light watering
Jun 4.3" 1.5" 2.8" 🚿 Regular watering
Jul 4.3" 2.1" 2.2" 🚿 Regular watering
Aug 4.3" 2" 2.3" 🚿 Regular watering
Sep 4.3" 1.8" 2.5" 🚿 Regular watering
Oct 2.1" 0" ❄️ Dormant
Nov 1.6" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Cascade County). Supplement amounts are based on average rainfall — 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" — 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.

Mizuna needs ~459 GDD — county provides 1,531 GDD Excellent fit

Mizuna Planting Timeline — Cascade County, MT

Mizuna Planting Calendar

Activity When Date Range
Start Indoors April 7 Apr 7 – Apr 21
Transplant Outdoors May 19 May 19 – Jun 2
Direct Sow May 12 May 12 – Jun 2
Harvest June 23 Jun 23 – Jul 21
Fall Sowing June 29 Jun 29 – Jul 13

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

30–45 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 4b

📆 Growing Season

125 days in Cascade County

Growing Tips for Mizuna in Cascade County

Direct sow Mizuna outdoors after May 19 in Cascade County when soil has warmed and frost danger has passed.

Your generous 125.0-day season in Cascade 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.

Cascade County receives only 22" of rain annually. Mizuna needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Cascade County, MT?

Cascade County is in Zone 4b with an average last frost of May 19. Plan your Mizuna planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cascade County, MT?

Cascade County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 19 and first fall frost is September 21.

🌱

Your Cascade County Garden Planner — Free

A 24-page printable planner built for Cascade County (Zone 4b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

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

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.