Blog

When to Plant Leeks in Hardin County, TN

Hardin County, Tennessee Zone 7b May

Your May planting checklist for Hardin County, Tennessee

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost March 31
Avg. first frost October 28
Soil temp (4") 62°F
Watering Low
Pest pressure Moderate
Daylight 13.9 hrs
  1. Get leeks seeds going inside

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

June will be here before you know it — start on
  • First harvests: leeks

Instant PDF download. No spam, unsubscribe any time.

Leeks are a mild, sweet allium that produces long white shanks. They are more refined than onions and are a key ingredient in soups, stews, and gratins.

Hardin County, Tennessee is in USDA Zone 7b. The average last spring frost is March 31 and the first fall frost is October 28, giving you a growing season of approximately 211 days.

At an elevation of 3,095 feet, Hardin County receives approximately 53.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 93°F, providing good warmth for Leeks during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Leeks root diseases.

Hardin County, TN (Zone 7b) Long season
211 days
Last Spring Frost March 31
211 growing days
First Fall Frost October 28

Hardin County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (46 days to spare)
Start indoors: Feb 17 Transplant: Mar 24 🍅 Harvest: Jun 23 – Sep 8
Recommended (50%) ✓ Fits season (43 days to spare)
Start indoors: Feb 24 Transplant: Mar 31 🍅 Harvest: Jun 30 – Sep 15
Safe Start (90%) ✓ Fits season (43 days to spare)
Start indoors: Mar 12 Transplant: Apr 16 🍅 Harvest: Jul 16 – Oct 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 Hardin County

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

Soil pH

Your soil pH (5.4–6.7) overlaps with Leeks's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

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

How to Plant Leeks

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

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

Plant Water Budget

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

Monthly Watering Guide for Leeks

Leeks needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Leeks Needs Rainfall You Supplement Action
Jan 4.2" 0" ❄️ Dormant
Feb 4.2" 0" ❄️ Dormant
Mar 3.5" 5.2" 0" ✅ Rainfall sufficient
Apr 3.5" 3.7" 0" ✅ Rainfall sufficient
May 3.5" 4.7" 0" ✅ Rainfall sufficient
Jun 3.5" 4.8" 0" ✅ Rainfall sufficient
Jul 3.5" 6" 0" ✅ Rainfall sufficient
Aug 3.5" 4.9" 0" ✅ Rainfall sufficient
Sep 3.5" 3.5" 0" ✅ Rainfall sufficient
Oct 3.5" 3.9" 0" ✅ Rainfall sufficient
Nov 4.3" 0" ❄️ Dormant
Dec 4.1" 0" ❄️ Dormant

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

Leeks 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.

Leeks needs ~2,370 GDD — county provides 4,167 GDD Excellent fit

Leeks Planting Timeline — Hardin County, TN

Leeks Planting Calendar

Activity When Date Range
Start Indoors February 24 Feb 24 – Mar 10
Transplant Outdoors March 31 Mar 31 – Apr 14
Direct Sow March 17 Mar 17 – Apr 7
Harvest June 30 Jun 30 – Sep 15
Fall Sowing August 19 Aug 19 – Sep 2

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · Natural rainfall sufficient

📅 Days to Maturity

90–150 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7b

📆 Growing Season

211 days in Hardin County

Growing Tips for Leeks in Hardin County

Direct sow Leeks outdoors after March 31 in Hardin County when soil has warmed and frost danger has passed.

Common pests for Leeks in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 10-12 weeks before last frost. Transplant into trenches and hill soil around stems as they grow to increase the white portion. Harvest as needed.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Leeks in Hardin County, TN?

Hardin County is in Zone 7b with an average last frost of March 31. Plan your Leeks planting based on this frost date — see the calendar above for exact timing.

What planting zone is Hardin County, TN?

Hardin County, Tennessee is in USDA Hardiness Zone 7b. The average last spring frost is March 31 and first fall frost is October 28.

🌱

Your Hardin County Garden Planner — Free

A 24-page printable planner built for Hardin 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.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Hardin 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.