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When to plant Collard Greens in Garfield County County,

In Garfield County County, plant Collard Greens in spring between May 9 and May 30, once soil temps hold above 50°F. Garfield County County's last frost averages May 16, so be cautious and check the 10-day forecast before planting tender crops. For a fall crop, sow between June 29 and July 13 — roughly 75 days before the first frost on September 21.

When to Plant Collard Greens in Garfield County, MT

Garfield County, Montana Zone 4b June

Your June gardening checklist

Here's what deserves your attention in Garfield County, Montana this month. Everything below is tailored to Zone 4b and timed around your local frost dates.

Avg. last frost May 16
Avg. first frost September 21
Soil temp (4") 39°F
Watering High
Pest pressure High
Daylight 15.7 hrs
  1. Get collard greens seeds going inside

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

  2. Plant your fall garden: collard greens

    Your first frost is about 14 weeks away — plenty of time for these to mature.

Before July arrives, get these ready
  • First harvests: collard greens

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Collard greens are a heat-tolerant member of the cabbage family with large, sturdy leaves. They are a Southern staple and one of the most nutritious leafy greens.

Garfield County, Montana is in USDA Zone 4b. The average last spring frost is May 16 and the first fall frost is September 21, giving you a growing season of approximately 128 days.

At an elevation of 8,464 feet, Garfield County receives approximately 18.8 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Collard Greens to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Collard Greens successfully. Mulch heavily to conserve soil moisture.

Garfield County, MT (Zone 4b) Short season
128 days
Last Spring Frost May 16
128 growing days
First Fall Frost September 21

Garfield County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.9

Drainage

Well Drained

Collard Greens Planting Risk Windows

Early Start (70% safe) ✓ Fits season (12 days to spare)
Start indoors: Mar 29 Transplant: May 10 🍅 Harvest: Jul 5 – Sep 6
Recommended (50%) ✓ Fits season (9 days to spare)
Start indoors: Apr 4 Transplant: May 16 🍅 Harvest: Jul 11 – Sep 12
Safe Start (90%) ✓ Fits season (15 days to spare)
Start indoors: Apr 18 Transplant: May 30 🍅 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 Garfield County

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

Soil pH

Your soil pH (6.3–7.9) is more alkaline than Collard Greens prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Collard Greens.

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Collard Greens.

How to Plant Collard Greens

1"
Planting Depth
15"
Between Plants
24"
Between Rows

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

Succession Planting Collard Greens

2
successive plantings in your 128-day season

Sow every 6.3 weeks. Last sowing by Jul 08 to harvest before frost.

For a dedicated fall crop, sow by Jun 29.

Collard Greens Water Budget

Plant needs
0.8″/week
Rainfall provides
0.6″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 578 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Collard Greens

Collard Greens needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Collard Greens Needs Rainfall You Supplement Action
Jan 1.2" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 1.7" 0" ❄️ Dormant
May 3.5" 2.3" 1.2" 💧 Light watering
Jun 3.5" 1.4" 2.1" 🚿 Regular watering
Jul 3.5" 1.5" 2" 🚿 Regular watering
Aug 3.5" 2" 1.5" 💧 Light watering
Sep 3.5" 1.8" 1.7" 💧 Light watering
Oct 1.5" 0" ❄️ Dormant
Nov 1.4" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

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

Collard 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.

Collard Greens needs ~699 GDD — county provides 1,376 GDD Excellent fit

Collard Greens Planting Timeline — Garfield County, MT

Collard Greens Planting Calendar

Activity When Date Range
Start Indoors April 4 Apr 4 – Apr 18
Transplant Outdoors May 16 May 16 – May 30
Direct Sow May 9 May 9 – May 30
Harvest July 11 Jul 11 – Sep 12
Fall Sowing June 29 Jun 29 – Jul 13

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · 1-2 times/week

📅 Days to Maturity

55–75 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 4b

📆 Growing Season

128 days in Garfield County

Growing Tips for Collard Greens in Garfield County

Direct sow Collard Greens outdoors after May 16 in Garfield County when soil has warmed and frost danger has passed.

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

General growing tips

Start seeds indoors or direct sow 4-6 weeks before last frost. Harvest lower leaves first, leaving the growing tip intact. Flavor improves after exposure to frost.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries
  • Tomatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Collard Greens in Garfield County, MT?

Garfield County is in Zone 4b with an average last frost of May 16. Plan your Collard Greens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Garfield County, MT?

Garfield County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 16 and first fall frost is September 21.

When should I plant Collard Greens in Garfield County County, ?

In Garfield County County, , plant Collard Greens after the last frost (around May 16) and before the first frost (around September 21). Best results when soil holds above 50°F.

What growing zone is Garfield County County, for Collard Greens?

Garfield County County sits in USDA Zone 4b. Collard Greens grows reliably in zones 2a through 11b, so it's a good fit here.

Can Collard Greens grow in Garfield County County's climate?

Yes — Collard Greens grows well in Garfield County County's temperate climate. Garfield County County averages a 128-day frost-free season, with last frost around May 16 and first frost around September 21.

🌱

Your Garfield County Garden Planner — Free

A 22-page printable planner built for Garfield 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 Garfield County, MT. Local conditions may vary. Last updated: June 2026.

Sources & credits

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