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When to plant Fennel (herb) in St. Mary's County County,

St. Mary's County County's climate puts the Fennel (herb) spring window between March 22 and April 12. most warm-season crops establish quickly once soil holds above 60°F. A second sowing from August 26 to September 9 extends the harvest into fall.

When to Plant Fennel (herb) in St. Mary's County, MD

St. Mary's County, Maryland Zone 8a June

Your June game plan for St. Mary's County, Maryland

June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in St. Mary's County, Maryland.

Avg. last frost April 5
Avg. first frost November 4
Soil temp (4") 79°F
Watering Low
Pest pressure High
Daylight 14.6 hrs
  1. Pick fennel (herb)

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

A few tasks this June that'll pay off in July
  • 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.

St. Mary's County, Maryland is in USDA Zone 8a. The average last spring frost is April 5 and the first fall frost is November 4, giving you a growing season of approximately 213 days.

At an elevation of 156 feet, St. Mary's County receives approximately 41.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 92°F, providing good warmth for Fennel (herb) during the growing season.

St. Mary's County, MD (Zone 8a) Long season
213 days
Last Spring Frost April 5
213 growing days
First Fall Frost November 4
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St. Mary's County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.9

Drainage

Well Drained

Fennel (herb) Planting Risk Windows

Early Start (70% safe) ✓ Fits season (90 days to spare)
Start indoors: Feb 21 Transplant: Mar 21 🍅 Harvest: May 23 – Aug 1
Recommended (50%) ✓ Fits season (87 days to spare)
Start indoors: Mar 1 Transplant: Mar 29 🍅 Harvest: May 31 – Aug 9
Safe Start (90%) ✓ Fits season (100 days to spare)
Start indoors: Mar 22 Transplant: Apr 19 🍅 Harvest: Jun 21 – Aug 30

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 St. Mary's County

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

Soil pH

Your soil pH (5.5–6.9) is within Fennel (herb)'s preferred range (5.5–7.0).

Soil Texture

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

Organic Matter

Organic matter is moderate (3.0%). Annual compost additions will help Fennel (herb).

How to Plant Fennel (herb)

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

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

Succession Planting Fennel (herb)

4
successive plantings in your 213-day season

Sow every 6.9 weeks. Last sowing by Aug 06 to harvest before frost.

For a dedicated fall crop, sow by Aug 26.

Fennel (herb) Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 344 gal / 100 sq ft

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 3.1" 0" ❄️ Dormant
Feb 2.6" 0" ❄️ Dormant
Mar 3.3" 0" ❄️ Dormant
Apr 4.3" 3.3" 1" 💧 Light watering
May 4.3" 3.9" 0.4" 💧 Light watering
Jun 4.3" 4.3" 0" ✅ Rainfall sufficient
Jul 4.3" 4" 0.3" 💧 Light watering
Aug 4.3" 4.3" 0" ✅ Rainfall sufficient
Sep 4.3" 3.6" 0.7" 💧 Light watering
Oct 4.3" 3.4" 0.9" 💧 Light watering
Nov 4.3" 2.7" 1.6" 💧 Light watering
Dec 2.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in St. Mary's 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 ~1,425 GDD — county provides 4,047 GDD Excellent fit

Fennel (herb) Planting Timeline — St. Mary's County, MD

Fennel (herb) Planting Calendar

Activity When Date Range
Start Indoors March 1 Mar 1 – Mar 15
Transplant Outdoors March 29 Mar 29 – Apr 12
Direct Sow March 22 Mar 22 – Apr 12
Harvest May 31 May 31 – Aug 9
Fall Sowing August 26 Aug 26 – Sep 9

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors Transplant Outdoors Direct Sow
April Transplant Outdoors Direct Sow
May Harvest
June Harvest
July Harvest
August Fall Sowing Harvest
September Fall Sowing
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 8a

📆 Growing Season

213 days in St. Mary's County

Growing Tips for Fennel (herb) in St. Mary's County

Direct sow Fennel (herb) outdoors after April 05 in St. Mary's 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 St. Mary's County, MD?

St. Mary's County is in Zone 8a with an average last frost of April 5. Plan your Fennel (herb) planting based on this frost date — see the calendar above for exact timing.

What planting zone is St. Mary's County, MD?

St. Mary's County, Maryland is in USDA Hardiness Zone 8a. The average last spring frost is April 5 and first fall frost is November 4.

When should I plant Fennel (herb) in St. Mary's County County, ?

In St. Mary's County County, , plant Fennel (herb) after the last frost (around April 5) and before the first frost (around November 4). Best results when soil holds above 50°F.

What growing zone is St. Mary's County County, for Fennel (herb)?

St. Mary's County County sits in USDA Zone 8a. Fennel (herb) grows reliably in zones 4a through 10b, so it's a good fit here.

Can Fennel (herb) grow in St. Mary's County County's climate?

Yes — Fennel (herb) grows well in St. Mary's County County's temperate climate. St. Mary's County County averages a 213-day frost-free season, with last frost around April 5 and first frost around November 4.

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Your St. Mary's County Garden Planner — Free

A 22-page printable planner built for St. Mary's County (Zone 8a). 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 St. Mary's County, MD. Local conditions may vary. Last updated: June 2026.

Sources & credits

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