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When to Plant Collard Greens in Blaine County, ID

Blaine County, Idaho Zone 5b April

Blaine County, Idaho gardeners: here's your April plan

Your Blaine County, Idaho garden is entering a new phase. Here's what's on the schedule for April and why each task matters now.

Avg. last frost May 18
Avg. first frost October 3
Soil temp (4") 22°F
Watering High
Pest pressure Low
Daylight 13.2 hrs
May will be here before you know it — start on
  • Transplants going out: collard greens
  • Direct-sowing: 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.

Blaine County, Idaho is in USDA Zone 5b. The average last spring frost is May 18 and the first fall frost is October 3, giving you a growing season of approximately 138 days.

At an elevation of 7,128 feet, Blaine County receives approximately 17.7 inches of rainfall annually with predominantly loam soil. Summer highs average 84°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.

Blaine County, ID (Zone 5b) Short season
138 days
Last Spring Frost May 18
138 growing days
First Fall Frost October 3

Blaine County Soil Profile

Soil Type

Loam

Soil pH

6.7-8.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (22 days to spare)
Start indoors: Apr 1 Transplant: May 6 🍅 Harvest: Jul 1 – Sep 2
Recommended (50%) ✓ Fits season (19 days to spare)
Start indoors: Apr 13 Transplant: May 18 🍅 Harvest: Jul 13 – Sep 14
Safe Start (90%) ✓ Fits season (12 days to spare)
Start indoors: May 7 Transplant: Jun 11 🍅 Harvest: Aug 6 – Oct 8

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 Blaine County

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

Soil pH

Your soil pH (6.7–8.4) 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 Blaine 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 (2.2%). Annual compost additions will help Collard Greens.

How to Plant Collard Greens

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

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Collard Greens

2
successive plantings in your 138-day season

Sow every 6.3 weeks. Last sowing by Jul 20 to harvest before frost.

For a dedicated fall crop, sow by Jul 25.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.5″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 739 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 1.4" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 1.7" 0" ❄️ Dormant
May 3.5" 1.9" 1.6" 💧 Light watering
Jun 3.5" 1.2" 2.3" 🚿 Regular watering
Jul 3.5" 1.8" 1.7" 💧 Light watering
Aug 3.5" 2.2" 1.3" 💧 Light watering
Sep 3.5" 1.5" 2" 🚿 Regular watering
Oct 3.5" 1.4" 2.1" 🚿 Regular watering
Nov 1.3" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Blaine 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 ~845 GDD — county provides 1,794 GDD Excellent fit

Collard Greens Planting Timeline — Blaine County, ID

Collard Greens Planting Calendar

Activity When Date Range
Start Indoors April 13 Apr 13 – Apr 27
Transplant Outdoors May 18 May 18 – Jun 1
Direct Sow May 4 May 4 – May 25
Harvest July 13 Jul 13 – Sep 14
Fall Sowing July 25 Jul 25 – Aug 8

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 Transplant Outdoors
July Fall Sowing Harvest
August Fall Sowing 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 5b

📆 Growing Season

138 days in Blaine County

Growing Tips for Collard Greens in Blaine County

Direct sow Collard Greens outdoors after May 18 in Blaine 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 Blaine County, ID?

Blaine County is in Zone 5b with an average last frost of May 18. Plan your Collard Greens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Blaine County, ID?

Blaine County, Idaho is in USDA Hardiness Zone 5b. The average last spring frost is May 18 and first fall frost is October 3.

🌱

Your Blaine County Garden Planner — Free

A 24-page printable planner built for Blaine County (Zone 5b). 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 Blaine County, ID. 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.