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When to plant Fennel in Au Gres, MI

Plant Fennel in Au Gres during the brief May 19–June 9 window. With 147 frost-free days, fall plantings can't mature before October 6.

When to Plant Fennel in Au Gres, MI

Arenac County, Michigan Zone 5b July

July in the garden — Arenac County, Michigan

July rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Arenac County, Michigan.

Avg. last frost May 12
Avg. first frost October 6
Soil temp (4") 78°F
Watering Moderate
Pest pressure High
Daylight 15 hrs
  1. Start fennel indoors

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

  2. Harvest fennel as they ripen

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

Looking ahead to August
  • First harvests: 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.

Au Gres, Michigan is in USDA Zone 5b. The average last spring frost is May 12 and the first fall frost is October 6, giving you a growing season of approximately 147 days.

At an elevation of 1,015 feet, Arenac County receives approximately 30.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Fennel during the growing season.

Au Gres, MI (Zone 5b) Short season
147 days
Last Spring Frost May 12
147 growing days
First Fall Frost October 6

Au Gres Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.1

Drainage

Well Drained

Fennel Planting Risk Windows

Early Start (70% safe) ✓ Fits season (28 days to spare)
Start indoors: Mar 11 Transplant: May 20 🍅 Harvest: Jul 22 – Sep 2
Recommended (50%) ✓ Fits season (28 days to spare)
Start indoors: Mar 17 Transplant: May 26 🍅 Harvest: Jul 28 – Sep 8
Safe Start (90%) ✓ Fits season (30 days to spare)
Start indoors: Mar 30 Transplant: Jun 8 🍅 Harvest: Aug 10 – Sep 21

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 Au Gres

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

Soil pH

Your soil pH (6.2–7.1) overlaps with Fennel's range (5.5–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Fennel.

Organic Matter

Organic matter is excellent (4.6%) — Fennel will thrive.

How to Plant Fennel

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

Succession Planting Fennel

2
successive plantings in your 147-day season

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

Fennel Water Budget

Plant needs
0.6″/week
Rainfall provides
0.9″/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 1.4" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 2.6" 0" ❄️ Dormant
May 2.6" 3.9" 0" ✅ Rainfall sufficient
Jun 2.6" 3.9" 0" ✅ Rainfall sufficient
Jul 2.6" 3.6" 0" ✅ Rainfall sufficient
Aug 2.6" 3.2" 0" ✅ Rainfall sufficient
Sep 2.6" 2.6" 0" ✅ Rainfall sufficient
Oct 2.6" 2.2" 0.4" 💧 Light watering
Nov 2" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Arenac 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 ~1,088 GDD — county provides 2,131 GDD Excellent fit

Fennel Planting Timeline — Au Gres, MI

Fennel Planting Calendar

Activity When Date Range
Start Indoors March 17 Mar 17 – Mar 31
Transplant Outdoors May 26 May 26 – Jun 9
Direct Sow May 19 May 19 – Jun 9
Harvest July 28 Jul 28 – Sep 8

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

Month-by-Month Timeline

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

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 5b

📆 Growing Season

147 days in Arenac County

Growing Tips for Fennel in Au Gres

Direct sow Fennel outdoors after May 12 in Arenac 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 →

When should I plant Fennel in Au Gres, MI?

In Au Gres, MI, plant Fennel after the last frost (around May 12) and before the first frost (around October 6). Best results when soil holds above 50°F.

What growing zone is Au Gres, MI for Fennel?

Au Gres sits in USDA Zone 5b. Fennel grows reliably in zones 4a through 10b, so it's a good fit here.

Can Fennel grow in Au Gres's climate?

Yes — Fennel grows well in Au Gres's temperate climate. Au Gres averages a 147-day frost-free season, with last frost around May 12 and first frost around October 6.

🌱

Your Arenac County Garden Planner — Free

A 22-page printable planner built for Arenac County (Zone 5b). 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 Arenac County, MI. Local conditions may vary. Last updated: July 2026.