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When to Plant Mustard Greens in Gallatin County, MT

Gallatin County, Montana Zone 4b April

April in the garden — Gallatin County, Montana

Each item below is timed to Gallatin County, Montana's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost June 8
Avg. first frost September 19
Soil temp (4") 15°F
Watering High
Pest pressure Low
Daylight 13.3 hrs

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Mustard greens are fast-growing brassicas with a spicy, peppery kick. They come in green, red, and purple varieties and are excellent cooked or in salads.

Gallatin County, Montana is in USDA Zone 4b. The average last spring frost is June 8 and the first fall frost is September 19, giving you a growing season of approximately 103 days.

At an elevation of 8,376 feet, Gallatin County receives approximately 12.4 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Mustard Greens to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Mustard Greens successfully. Mulch heavily to conserve soil moisture.

Gallatin County, MT (Zone 4b) Short season
103 days
Last Spring Frost June 8
103 growing days
First Fall Frost September 19

Gallatin County Soil Profile

Soil Type

Loam

Soil pH

6.2-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (9 days to spare)
Start indoors: Apr 13 Transplant: May 25 🍅 Harvest: Jun 29 – Aug 31
Recommended (50%) ✓ Fits season (5 days to spare)
Start indoors: Apr 27 Transplant: Jun 8 🍅 Harvest: Jul 13 – Sep 14
Safe Start (90%) ✓ Fits season (8 days to spare)
Start indoors: May 9 Transplant: Jun 20 🍅 Harvest: Jul 25 – Sep 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 Gallatin County

How your county's soil matches Mustard Greens's growing requirements.

Soil pH

Your soil pH (6.2–8.1) is more alkaline than Mustard Greens prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Gallatin County is excellent for Mustard Greens — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Mustard Greens.

How to Plant Mustard Greens

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 Mustard Greens

4
successive plantings in your 103-day season

Sow every 3.4 weeks. Last sowing by Jul 31 to harvest before frost.

For a dedicated fall crop, sow by Jun 27.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.5″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 214 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Mustard Greens

Mustard Greens needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Mustard Greens Needs Rainfall You Supplement Action
Jan 0.8" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.1" 0" ❄️ Dormant
Apr 1.3" 0" ❄️ Dormant
May 1.3" 0" ❄️ Dormant
Jun 3" 0.8" 2.2" 🚿 Regular watering
Jul 3" 1" 2" 🚿 Regular watering
Aug 3" 1.5" 1.5" 🚿 Regular watering
Sep 3" 1" 2" 🚿 Regular watering
Oct 1.1" 0" ❄️ Dormant
Nov 1" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Gallatin County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Mustard Greens 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.

Mustard Greens needs ~460 GDD — county provides 1,184 GDD Excellent fit

Mustard Greens Planting Timeline — Gallatin County, MT

Mustard Greens Planting Calendar

Activity When Date Range
Start Indoors April 27 Apr 27 – May 11
Transplant Outdoors June 8 Jun 8 – Jun 22
Direct Sow June 1 Jun 1 – Jun 22
Harvest July 13 Jul 13 – Sep 14
Fall Sowing June 27 Jun 27 – Jul 11

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.7"/week · Only during dry spells

📅 Days to Maturity

30–50 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 4b

📆 Growing Season

103 days in Gallatin County

Growing Tips for Mustard Greens in Gallatin County

Direct sow Mustard Greens outdoors after June 08 in Gallatin County when soil has warmed and frost danger has passed.

Common pests for Mustard Greens 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 early spring or fall. Harvest young leaves for milder flavor. Plants bolt quickly in heat so grow as a cool-season crop or provide shade.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Mustard Greens in Gallatin County, MT?

Gallatin County is in Zone 4b with an average last frost of June 8. Plan your Mustard Greens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Gallatin County, MT?

Gallatin County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is June 8 and first fall frost is September 19.

🌱

Your Gallatin County Garden Planner — Free

A 24-page printable planner built for Gallatin 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.

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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 Gallatin County, MT. Local conditions may vary. Last updated: April 2026.

Sources & credits

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