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When to Plant Dill in Union County, TN

Union County, Tennessee Zone 7b May

Union County, Tennessee gardeners: here's your May plan

Your Union County, Tennessee garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost April 10
Avg. first frost October 29
Soil temp (4") 67°F
Watering Moderate
Pest pressure Moderate
Daylight 13.9 hrs
  1. Start dill indoors

    You're about 25 weeks out from your last frost — the perfect window to get these germinating indoors.

  2. Bring in the dill

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

June prep starts now
  • First harvests: dill

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Dill is a feathery annual herb with aromatic leaves and seeds. Its fine foliage and umbrella-shaped flower heads attract beneficial insects to the garden.

Union County, Tennessee is in USDA Zone 7b. The average last spring frost is April 10 and the first fall frost is October 29, giving you a growing season of approximately 202 days.

At an elevation of 1,122 feet, Union County receives approximately 50.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Dill during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Dill root diseases.

Union County, TN (Zone 7b) Long season
202 days
Last Spring Frost April 10
202 growing days
First Fall Frost October 29
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Union County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (102 days to spare)
Start indoors: Feb 28 Transplant: Mar 28 🍅 Harvest: May 9 – Jul 11
Recommended (50%) ✓ Fits season (104 days to spare)
Start indoors: Mar 6 Transplant: Apr 3 🍅 Harvest: May 15 – Jul 17
Safe Start (90%) ✓ Fits season (100 days to spare)
Start indoors: Mar 21 Transplant: Apr 18 🍅 Harvest: May 30 – Aug 1

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 Union County

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

Soil pH

Your soil pH (5.8–6.6) is within Dill's preferred range (5.5–7.0).

Soil Texture

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

Organic Matter

Organic matter is moderate (2.9%). Annual compost additions will help Dill.

How to Plant Dill

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

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

Succession Planting Dill

6
successive plantings in your 202-day season

Sow every 4.6 weeks. Last sowing by Aug 30 to harvest before frost.

For a dedicated fall crop, sow by Aug 20.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Dill

Dill needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Dill Needs Rainfall You Supplement Action
Jan 4.8" 0" ❄️ Dormant
Feb 3.4" 0" ❄️ Dormant
Mar 5.2" 0" ❄️ Dormant
Apr 2.2" 3.8" 0" ✅ Rainfall sufficient
May 2.2" 3.7" 0" ✅ Rainfall sufficient
Jun 2.2" 4.8" 0" ✅ Rainfall sufficient
Jul 2.2" 5.6" 0" ✅ Rainfall sufficient
Aug 2.2" 4.5" 0" ✅ Rainfall sufficient
Sep 2.2" 4.1" 0" ✅ Rainfall sufficient
Oct 2.2" 3.3" 0" ✅ Rainfall sufficient
Nov 3.4" 0" ❄️ Dormant
Dec 4.1" 0" ❄️ Dormant

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

Dill 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.

Dill needs ~800 GDD — county provides 3,232 GDD Excellent fit

Dill Planting Timeline — Union County, TN

Dill Planting Calendar

Activity When Date Range
Start Indoors March 6 Mar 6 – Mar 20
Transplant Outdoors April 3 Apr 3 – Apr 17
Direct Sow March 27 Mar 27 – Apr 17
Harvest May 15 May 15 – Jul 17
Fall Sowing August 20 Aug 20 – Sep 3

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 5.5–7 · Your soil: ideal

🗺️ USDA Zone

Zone 7b

📆 Growing Season

202 days in Union County

Growing Tips for Dill in Union County

Direct sow Dill outdoors after April 10 in Union County when soil has warmed and frost danger has passed.

Your generous 202.0-day season in Union County allows multiple plantings of Dill. Sow every 20.0 days for continuous harvest.

Common pests for Dill 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 as dill has a taproot and dislikes transplanting. Succession sow for continuous leaf harvest. Allow some plants to flower for seeds and to attract beneficial insects.

Companion Planting

Good Companions

Avoid Planting Near

  • Carrots
  • Tomatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Dill in Union County, TN?

Union County is in Zone 7b with an average last frost of April 10. Plan your Dill planting based on this frost date — see the calendar above for exact timing.

What planting zone is Union County, TN?

Union County, Tennessee is in USDA Hardiness Zone 7b. The average last spring frost is April 10 and first fall frost is October 29.

🌱

Your Union County Garden Planner — Free

A 24-page printable planner built for Union County (Zone 7b). 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 Union County, TN. 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.