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When to plant Fennel in Aroostook County County,

In Aroostook County County, Fennel is a single-season spring crop — there's no second fall window. Plant June 1–June 22 for an 90-day harvest, finishing well before the September 24 first frost.

When to Plant Fennel in Aroostook County, ME

Aroostook County, Maine Zone 4a June

Top priorities for Aroostook County, Maine gardeners in June

Each item below is timed to Aroostook County, Maine's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost May 18
Avg. first frost September 24
Soil temp (4") 61°F
Watering Moderate
Pest pressure Moderate
Daylight 15.6 hrs
  1. Harden off and plant fennel

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

  2. Seed fennel outdoors

    Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.

Get ahead of July
  • 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.

Aroostook County, Maine is in USDA Zone 4a. The average last spring frost is May 18 and the first fall frost is September 24, giving you a growing season of approximately 129 days.

At an elevation of 314 feet, Aroostook County receives approximately 39.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 78°F, so choose short-season varieties of Fennel to ensure they mature before fall.

Aroostook County, ME (Zone 4a) Short season
129 days
Last Spring Frost May 18
129 growing days
First Fall Frost September 24
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Aroostook County Soil Profile

Soil Type

Silt Loam

Soil pH

4.9-6.3

Drainage

Well Drained

Fennel Planting Risk Windows

Early Start (70% safe) ✓ Fits season (3 days to spare)
Start indoors: Mar 10 Transplant: Jun 2 🍅 Harvest: Aug 4 – Sep 15
Recommended (50%) ✓ Fits season (3 days to spare)
Start indoors: Mar 16 Transplant: Jun 8 🍅 Harvest: Aug 10 – Sep 21
Safe Start (90%) ✓ Fits season (0 days to spare)
Start indoors: Mar 30 Transplant: Jun 22 🍅 Harvest: Aug 24 – Oct 5

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 Aroostook County

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

Soil pH

Your soil pH (4.9–6.3) overlaps with Fennel's range (5.5–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.8%). Annual compost additions will help Fennel.

How to Plant Fennel

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

Succession Planting Fennel

2
successive plantings in your 129-day season

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

Fennel Water Budget

Plant needs
0.6″/week
Rainfall provides
1.3″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 2.8" 0" ❄️ Dormant
Feb 2.7" 0" ❄️ Dormant
Mar 3.3" 0" ❄️ Dormant
Apr 3.5" 0" ❄️ Dormant
May 2.6" 3.3" 0" ✅ Rainfall sufficient
Jun 2.6" 3.7" 0" ✅ Rainfall sufficient
Jul 2.6" 3.6" 0" ✅ Rainfall sufficient
Aug 2.6" 3.6" 0" ✅ Rainfall sufficient
Sep 2.6" 3.9" 0" ✅ Rainfall sufficient
Oct 3.2" 0" ❄️ Dormant
Nov 2.9" 0" ❄️ Dormant
Dec 3" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Aroostook County). 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 ~638 GDD — county provides 1,096 GDD Excellent fit

Fennel Planting Timeline — Aroostook County, ME

Fennel Planting Calendar

Activity When Date Range
Start Indoors March 16 Mar 16 – Mar 30
Transplant Outdoors June 8 Jun 8 – Jun 22
Direct Sow June 1 Jun 1 – Jun 22
Harvest August 10 Aug 10 – Sep 21

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.6"/week · Natural rainfall sufficient

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 5.5–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 4a

📆 Growing Season

129 days in Aroostook County

Growing Tips for Fennel in Aroostook County

Direct sow Fennel outdoors after May 18 in Aroostook County 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 Aroostook County, ME?

Aroostook County is in Zone 4a with an average last frost of May 18. Plan your Fennel planting based on this frost date — see the calendar above for exact timing.

What planting zone is Aroostook County, ME?

Aroostook County, Maine is in USDA Hardiness Zone 4a. The average last spring frost is May 18 and first fall frost is September 24.

When should I plant Fennel in Aroostook County, ?

In Aroostook County, , plant Fennel after the last frost (around May 18) and before the first frost (around September 24). Best results when soil holds above 50°F.

What growing zone is Aroostook County, for Fennel?

Aroostook County sits in USDA Zone 4a. Fennel grows reliably in zones 4a through 10b, so it's a good fit here.

Can Fennel grow in Aroostook County's climate?

Yes — Fennel grows well in Aroostook County's temperate climate. Aroostook County averages a 129-day frost-free season, with last frost around May 18 and first frost around September 24.

🌱

Your Aroostook County Garden Planner — Free

A 22-page printable planner built for Aroostook County (Zone 4a). 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 Aroostook County, ME. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.