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When to Plant Mustard Greens in Palmer, AK

Palmer, Alaska Zone 4b May

Your May gardening checklist

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Palmer, Alaska.

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. Harden off and plant mustard greens

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

  2. Direct-sow mustard greens

    These tolerate cool soil, so you're not gambling by sowing now.

Before June arrives, get these ready
  • Starting indoors: mustard greens
  • First harvests: mustard greens
  • Fall sowing: mustard greens

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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.

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 Mustard Greens to ensure they mature before fall. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Mustard Greens 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 (24 days to spare)
Start indoors: Mar 29 Transplant: May 10 🍅 Harvest: Jun 14 – Aug 16
Recommended (50%) ✓ Fits season (26 days to spare)
Start indoors: Apr 5 Transplant: May 17 🍅 Harvest: Jun 21 – Aug 23
Safe Start (90%) ✓ Fits season (14 days to spare)
Start indoors: Apr 27 Transplant: Jun 8 🍅 Harvest: Jul 13 – Sep 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 Palmer

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

Soil pH

Your soil pH (4.9–6.7) is more acidic than Mustard Greens prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Mustard Greens.

Organic Matter

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

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 124-day season

Sow every 3.4 weeks. Last sowing by Jul 30 to harvest before frost.

For a dedicated fall crop, sow by Jun 26.

Plant Water Budget

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

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 2.5" 0" ❄️ Dormant
Feb 2.5" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 1.6" 0" ❄️ Dormant
May 3" 2.2" 0.8" 💧 Light watering
Jun 3" 4.3" 0" ✅ Rainfall sufficient
Jul 3" 7.4" 0" ✅ Rainfall sufficient
Aug 3" 7.7" 0" ✅ Rainfall sufficient
Sep 3" 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.

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 ~70 GDD — county provides 217 GDD Excellent fit

Mustard Greens Planting Timeline — Palmer, AK

Mustard Greens 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 June 21 Jun 21 – Aug 23
Fall Sowing June 26 Jun 26 – Jul 10

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 Fall Sowing Harvest
July Fall Sowing Harvest
August Harvest
September
October
November
December
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Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.7"/week · Natural rainfall sufficient

📅 Days to Maturity

30–50 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 4b

📆 Growing Season

124 days in Palmer

Growing Tips for Mustard Greens in Palmer

Direct sow Mustard Greens outdoors after May 17 in Palmer 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 Palmer, AK?

Palmer is in Zone 4b with an average last frost of May 17. Plan your Mustard Greens 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.

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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

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