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When to Plant Fennel (herb) in Stevens County, MN

Stevens County, Minnesota Zone 4b May

Your May planting checklist for Stevens County, Minnesota

Welcome to May in Zone 4b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 2
Avg. first frost October 6
Soil temp (4") 54°F
Watering Low
Pest pressure Low
Daylight 14.7 hrs
To set up a strong June, finish these tasks
  • Starting indoors: fennel (herb)
  • First harvests: fennel (herb)

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Herb fennel is grown for its aromatic leaves, stalks, and seeds rather than a bulb. It has a strong anise flavor and its flowers attract beneficial insects.

Stevens County, Minnesota is in USDA Zone 4b. The average last spring frost is May 2 and the first fall frost is October 6, giving you a growing season of approximately 157 days.

At an elevation of 1,259 feet, Stevens County receives approximately 37.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Fennel (herb) to ensure they mature before fall.

Stevens County, MN (Zone 4b) Moderate season
157 days
Last Spring Frost May 2
157 growing days
First Fall Frost October 6
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Stevens County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (31 days to spare)
Start indoors: Mar 15 Transplant: Apr 19 🍅 Harvest: Jun 21 – Aug 30
Recommended (50%) ✓ Fits season (31 days to spare)
Start indoors: Mar 21 Transplant: Apr 25 🍅 Harvest: Jun 27 – Sep 5
Safe Start (90%) ✓ Fits season (29 days to spare)
Start indoors: Apr 3 Transplant: May 8 🍅 Harvest: Jul 10 – Sep 18

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 Stevens County

How your county's soil matches Fennel (herb)'s growing requirements.

Soil pH

Your soil pH (6.1–7.0) is within Fennel (herb)'s preferred range (5.5–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.0%) — Fennel (herb) will thrive.

How to Plant Fennel (herb)

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 Fennel (herb)

3
successive plantings in your 157-day season

Sow every 6.9 weeks. Last sowing by Jul 08 to harvest before frost.

For a dedicated fall crop, sow by Jul 14.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
Watering frequency Only during dry spells
Season total 4 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Fennel (herb)

Fennel (herb) needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Fennel (herb) Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 4.1" 0" ❄️ Dormant
May 4.3" 4.7" 0" ✅ Rainfall sufficient
Jun 4.3" 4.9" 0" ✅ Rainfall sufficient
Jul 4.3" 3.6" 0.7" 💧 Light watering
Aug 4.3" 3.5" 0.8" 💧 Light watering
Sep 4.3" 2.9" 1.4" 💧 Light watering
Oct 4.3" 2.8" 1.5" 💧 Light watering
Nov 2.8" 0" ❄️ Dormant
Dec 2.3" 0" ❄️ Dormant

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

Fennel (herb) 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 (herb) needs ~806 GDD — county provides 1,687 GDD Excellent fit

Fennel (herb) Planting Timeline — Stevens County, MN

Fennel (herb) Planting Calendar

Activity When Date Range
Start Indoors March 21 Mar 21 – Apr 4
Transplant Outdoors April 25 Apr 25 – May 9
Direct Sow April 25 Apr 25 – May 16
Harvest June 27 Jun 27 – Sep 5
Fall Sowing July 14 Jul 14 – Jul 28

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 5.5–7 · Your soil: ideal

🗺️ USDA Zone

Zone 4b

📆 Growing Season

157 days in Stevens County

Growing Tips for Fennel (herb) in Stevens County

Direct sow Fennel (herb) outdoors after May 02 in Stevens County when soil has warmed and frost danger has passed.

Common pests for Fennel (herb) 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 spring or fall. Unlike Florence fennel, herb fennel does not form a bulb. Harvest fronds as needed and seeds when they turn brown. Self-sows readily.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Peppers
  • Green Beans

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Fennel (herb) in Stevens County, MN?

Stevens County is in Zone 4b with an average last frost of May 2. Plan your Fennel (herb) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Stevens County, MN?

Stevens County, Minnesota is in USDA Hardiness Zone 4b. The average last spring frost is May 2 and first fall frost is October 6.

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Your Stevens County Garden Planner — Free

A 24-page printable planner built for Stevens County (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 Stevens County, MN. 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.