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When to Plant Mustard Greens in Sitka City and Borough, AK

Sitka City and Borough, Alaska Zone 7b May

Sitka City and Borough, Alaska gardeners: here's your May plan

Welcome to May in Zone 7b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 20
Avg. first frost October 24
Soil temp (4") 64°F
Watering Critical
Pest pressure Moderate
Daylight 16.2 hrs
  1. Time to start mustard greens inside

    These need a head start before your last frost (April 20). Sow into cells now so you're ready to transplant in a few weeks.

  2. Pick mustard greens

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

Looking ahead to June
  • First harvests: 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.

Sitka City and Borough, Alaska is in USDA Zone 7b. The average last spring frost is April 20 and the first fall frost is October 24, giving you a growing season of approximately 187 days.

At an elevation of 1,935 feet, Sitka City and Borough receives approximately 21.8 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.

Sitka City and Borough, AK (Zone 7b) Moderate season
187 days
Last Spring Frost April 20
187 growing days
First Fall Frost October 24

Sitka City and Borough Soil Profile

Soil Type

Silt Loam

Soil pH

4.9-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (91 days to spare)
Start indoors: Mar 8 Transplant: Apr 12 🍅 Harvest: May 17 – Jul 19
Recommended (50%) ✓ Fits season (89 days to spare)
Start indoors: Mar 16 Transplant: Apr 20 🍅 Harvest: May 25 – Jul 27
Safe Start (90%) ✓ Fits season (83 days to spare)
Start indoors: Apr 8 Transplant: May 13 🍅 Harvest: Jun 17 – Aug 19

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 Sitka City and Borough

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

Soil pH

Your soil pH (4.9–6.4) is more acidic than Mustard Greens prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.5%) — Mustard Greens will thrive.

How to Plant Mustard Greens

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

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

Succession Planting Mustard Greens

7
successive plantings in your 187-day season

Sow every 3.4 weeks. Last sowing by Sep 04 to harvest before frost.

For a dedicated fall crop, sow by Aug 15.

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 350 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 1" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 0.7" 0" ❄️ Dormant
Apr 3" 0.6" 2.4" 🚿 Regular watering
May 3" 1.1" 1.9" 🚿 Regular watering
Jun 3" 1.5" 1.5" 🚿 Regular watering
Jul 3" 2.8" 0.2" 💧 Light watering
Aug 3" 3.9" 0" ✅ Rainfall sufficient
Sep 3" 3.5" 0" ✅ Rainfall sufficient
Oct 3" 2.9" 0.1" 💧 Light watering
Nov 1.6" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Sitka City and Borough). 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 327 GDD Excellent fit

Mustard Greens Planting Timeline — Sitka City and Borough, AK

Mustard Greens Planting Calendar

Activity When Date Range
Start Indoors March 16 Mar 16 – Mar 30
Transplant Outdoors April 20 Apr 20 – May 4
Direct Sow April 6 Apr 6 – Apr 27
Harvest May 25 May 25 – Jul 27
Fall Sowing August 15 Aug 15 – Aug 29

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 7b

📆 Growing Season

187 days in Sitka City and Borough

Growing Tips for Mustard Greens in Sitka City and Borough

Direct sow Mustard Greens outdoors after April 20 in Sitka City and Borough when soil has warmed and frost danger has passed.

Your generous 187.0-day season in Sitka City and Borough allows multiple plantings of Mustard Greens. Sow every 15.0 days for continuous harvest.

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 Sitka City and Borough, AK?

Sitka City and Borough is in Zone 7b with an average last frost of April 20. Plan your Mustard Greens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Sitka City and Borough, AK?

Sitka City and Borough, Alaska is in USDA Hardiness Zone 7b. The average last spring frost is April 20 and first fall frost is October 24.

🌱

Your Sitka City and Borough Garden Planner — Free

A 24-page printable planner built for Sitka City and Borough (Zone 7b). 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 Sitka City and Borough, 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.