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When to Plant Fennel in Sitka City and Borough, AK

Sitka City and Borough, Alaska Zone 7b May

What to do in May

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. Transplant fennel outside

    Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.

Get ahead of June
  • Starting indoors: fennel

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Florence fennel is grown for its swollen bulb-like stem base, which has a mild anise flavor. It is crisp raw in salads and sweet when roasted or braised.

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 Fennel 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 (70 days to spare)
Start indoors: Feb 22 Transplant: Apr 26 🍅 Harvest: Jun 28 – Aug 9
Recommended (50%) ✓ Fits season (68 days to spare)
Start indoors: Mar 2 Transplant: May 4 🍅 Harvest: Jul 6 – Aug 17
Safe Start (90%) ✓ Fits season (62 days to spare)
Start indoors: Mar 25 Transplant: May 27 🍅 Harvest: Jul 29 – Sep 9

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 Fennel's growing requirements.

Soil pH

Your soil pH (4.9–6.4) overlaps with Fennel's range (5.5–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

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

How to Plant Fennel

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

Succession Planting Fennel

3
successive plantings in your 187-day season

Sow every 6.9 weeks. Last sowing by Jul 26 to harvest before frost.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
0.5″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 184 gal / 100 sq ft

Monthly Watering Guide for Fennel

Fennel needs approximately 0.6 inches of water per week (2.6" per month). Here's how your county's rainfall compares month by month.

Month Fennel Needs Rainfall You Supplement Action
Jan 1" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 0.7" 0" ❄️ Dormant
Apr 2.6" 0.6" 2" 🚿 Regular watering
May 2.6" 1.1" 1.5" 🚿 Regular watering
Jun 2.6" 1.5" 1.1" 💧 Light watering
Jul 2.6" 2.8" 0" ✅ Rainfall sufficient
Aug 2.6" 3.9" 0" ✅ Rainfall sufficient
Sep 2.6" 3.5" 0" ✅ Rainfall sufficient
Oct 2.6" 2.9" 0" ✅ Rainfall sufficient
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.

Fennel 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.

Fennel needs ~131 GDD — county provides 327 GDD Excellent fit

Fennel Planting Timeline — Sitka City and Borough, AK

Fennel Planting Calendar

Activity When Date Range
Start Indoors March 2 Mar 2 – Mar 16
Transplant Outdoors May 4 May 4 – May 18
Direct Sow April 27 Apr 27 – May 18
Harvest July 6 Jul 6 – Aug 17

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.6"/week · Only during dry spells

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 5.5–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7b

📆 Growing Season

187 days in Sitka City and Borough

Growing Tips for Fennel in Sitka City and Borough

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

Common pests for Fennel in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow in late summer for fall harvest to reduce bolting. Hill soil around bulbs as they enlarge. Harvest when bulbs are tennis-ball sized before they elongate.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Peppers
  • Beans

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Fennel in Sitka City and Borough, AK?

Sitka City and Borough is in Zone 7b with an average last frost of April 20. Plan your Fennel 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.

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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.