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When to Plant Fennel in Box Butte County, NE

Box Butte County, Nebraska Zone 5a May

What to do in May

A quick May briefing for Box Butte County, Nebraska gardeners — what's urgent, what's next, and what can wait.

Avg. last frost May 11
Avg. first frost October 1
Soil temp (4") 54°F
Watering Moderate
Pest pressure Low
Daylight 14.4 hrs
  1. Plant out fennel

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

  2. Scatter fennel into prepared beds

    Mark the row. Birds and stray feet both have opinions about unmarked beds.

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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.

Box Butte County, Nebraska is in USDA Zone 5a. The average last spring frost is May 11 and the first fall frost is October 1, giving you a growing season of approximately 143 days.

At an elevation of 1,021 feet, Box Butte County receives approximately 27.1 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Fennel to ensure they mature before fall.

Box Butte County, NE (Zone 5a) Short season
143 days
Last Spring Frost May 11
143 growing days
First Fall Frost October 1

Box Butte County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (24 days to spare)
Start indoors: Mar 9 Transplant: May 18 🍅 Harvest: Jul 20 – Aug 31
Recommended (50%) ✓ Fits season (24 days to spare)
Start indoors: Mar 16 Transplant: May 25 🍅 Harvest: Jul 27 – Sep 7
Safe Start (90%) ✓ Fits season (23 days to spare)
Start indoors: Mar 28 Transplant: Jun 6 🍅 Harvest: Aug 8 – Sep 19

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 Box Butte County

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

Soil pH

Your soil pH (6.2–7.3) overlaps with Fennel's range (5.5–7.0), though not a perfect match.

Soil Texture

The loam soil in Box Butte 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 143-day season

Sow every 6.9 weeks. Last sowing by Jul 03 to harvest before frost.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

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 1.7" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 2.8" 0" ❄️ Dormant
May 2.6" 3.2" 0" ✅ Rainfall sufficient
Jun 2.6" 1.8" 0.8" 💧 Light watering
Jul 2.6" 2.1" 0.5" 💧 Light watering
Aug 2.6" 2.6" 0" ✅ Rainfall sufficient
Sep 2.6" 2.3" 0.3" 💧 Light watering
Oct 2.6" 2.5" 0.1" 💧 Light watering
Nov 2.2" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Box Butte 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 ~750 GDD — county provides 1,430 GDD Excellent fit

Fennel Planting Timeline — Box Butte County, NE

Fennel Planting Calendar

Activity When Date Range
Start Indoors March 16 Mar 16 – Mar 30
Transplant Outdoors May 25 May 25 – Jun 8
Direct Sow May 18 May 18 – Jun 8
Harvest July 27 Jul 27 – Sep 7

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 5a

📆 Growing Season

143 days in Box Butte County

Growing Tips for Fennel in Box Butte County

Direct sow Fennel outdoors after May 11 in Box Butte 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 Box Butte County, NE?

Box Butte County is in Zone 5a with an average last frost of May 11. Plan your Fennel planting based on this frost date — see the calendar above for exact timing.

What planting zone is Box Butte County, NE?

Box Butte County, Nebraska is in USDA Hardiness Zone 5a. The average last spring frost is May 11 and first fall frost is October 1.

🌱

Your Box Butte County Garden Planner — Free

A 24-page printable planner built for Box Butte County (Zone 5a). 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 Box Butte County, NE. 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.