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When to Plant Kale in Palmer, AK

Palmer, Alaska Zone 4b May

Palmer, Alaska gardeners: here's your May plan

May is a pivotal month for Palmer, Alaska gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 17
Avg. first frost September 18
Soil temp (4") 51°F
Watering High
Pest pressure Low
Daylight 17.4 hrs
  1. Move kale into the garden

    Your last frost (May 17) has passed. These warm-season crops can handle outdoor soil now.

  2. Sow kale where they'll grow

    Mark the row. Birds and stray feet both have opinions about unmarked beds.

To set up a strong June, finish these tasks
  • Starting indoors: kale
  • Fall sowing: kale

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Kale is an exceptionally hardy, nutrient-dense green available in curly, lacinato, and Russian varieties. It tolerates heavy frost and often tastes sweeter after cold exposure.

Palmer, Alaska is in USDA Zone 4b. The average last spring frost is May 17 and the first fall frost is September 18, giving you a growing season of approximately 124 days.

At an elevation of 1,177 feet, Palmer receives approximately 52.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 69°F, so choose short-season varieties of Kale to ensure they mature before fall. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Kale root diseases.

Palmer, AK (Zone 4b) Short season
124 days
Last Spring Frost May 17
124 growing days
First Fall Frost September 18
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Palmer Soil Profile

Soil Type

Silt Loam

Soil pH

4.9-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (10 days to spare)
Start indoors: Mar 29 Transplant: May 10 🍅 Harvest: Jul 5 – Aug 30
Recommended (50%) ✓ Fits season (12 days to spare)
Start indoors: Apr 5 Transplant: May 17 🍅 Harvest: Jul 12 – Sep 6
Safe Start (90%) ✓ Fits season (0 days to spare)
Start indoors: Apr 27 Transplant: Jun 8 🍅 Harvest: Aug 3 – Sep 28

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 Palmer

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

Soil pH

Your soil pH (4.9–6.7) is more acidic than Kale prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Palmer is excellent for Kale — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Kale.

Organic Matter

Organic matter is excellent (6.8%) — Kale will thrive.

How to Plant Kale

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 Kale

2
successive plantings in your 124-day season

Sow every 5.7 weeks. Last sowing by Jul 10 to harvest before frost.

For a dedicated fall crop, sow by Jun 26.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
1.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Kale

Kale 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 Kale Needs Rainfall You Supplement Action
Jan 2.5" 0" ❄️ Dormant
Feb 2.5" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 1.6" 0" ❄️ Dormant
May 3.5" 2.2" 1.3" 💧 Light watering
Jun 3.5" 4.3" 0" ✅ Rainfall sufficient
Jul 3.5" 7.4" 0" ✅ Rainfall sufficient
Aug 3.5" 7.7" 0" ✅ Rainfall sufficient
Sep 3.5" 8.3" 0" ✅ Rainfall sufficient
Oct 6.5" 0" ❄️ Dormant
Nov 3.9" 0" ❄️ Dormant
Dec 3.3" 0" ❄️ Dormant

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

Kale 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.

Kale needs ~105 GDD — county provides 217 GDD Excellent fit

Kale Planting Timeline — Palmer, AK

Kale Planting Calendar

Activity When Date Range
Start Indoors April 5 Apr 5 – Apr 19
Transplant Outdoors May 17 May 17 – May 31
Direct Sow May 10 May 10 – May 31
Harvest July 12 Jul 12 – Sep 6
Fall Sowing June 26 Jun 26 – Jul 10

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
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · Natural rainfall sufficient

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 4b

📆 Growing Season

124 days in Palmer

Growing Tips for Kale in Palmer

Direct sow Kale outdoors after May 17 in Palmer when soil has warmed and frost danger has passed.

Common pests for Kale 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 or transplant in early spring or late summer. Harvest outer leaves first to keep plants productive. Kale overwinters in many climates and can provide greens all year.

Recommended Kale Varieties for Palmer

Cold-hardy kale that improves in flavor after frost

Winterbor Red Russian Dwarf Blue Curled

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries
  • Tomatoes

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Kale Seeds
Life Cycle Biennial
Pollination Cross-Pollinated (insects)
How to Collect Allow 2nd year flower stalks to dry. Harvest pods when tan.
Storage Store airtight; viable 5 years at 35°F, under 50% humidity.

Isolate 1/2 mile from other brassicas (broccoli, cabbage, etc.) — they all cross.

Frequently Asked Questions

When should I plant Kale in Palmer, AK?

Palmer is in Zone 4b with an average last frost of May 17. Plan your Kale planting based on this frost date — see the calendar above for exact timing.

What planting zone is Palmer, AK?

Palmer, Alaska is in USDA Hardiness Zone 4b. The average last spring frost is May 17 and first fall frost is September 18.

🌱

Your Palmer Garden Planner — Free

A 24-page printable planner built for Palmer (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 Palmer, AK. 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.