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When to Plant Leeks in Miller County, MO

Miller County, Missouri Zone 6b May

This month in Miller County, Missouri

A quick May briefing for Miller County, Missouri gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 6
Avg. first frost October 27
Soil temp (4") 65°F
Watering Low
Pest pressure Low
Daylight 14.1 hrs
  1. Indoor seed-starting week for leeks

    Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.

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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.

Miller County, Missouri is in USDA Zone 6b. The average last spring frost is April 6 and the first fall frost is October 27, giving you a growing season of approximately 204 days.

At an elevation of 1,086 feet, Miller County receives approximately 30.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Leeks during the growing season.

Miller County, MO (Zone 6b) Long season
204 days
Last Spring Frost April 6
204 growing days
First Fall Frost October 27

Miller County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (35 days to spare)
Start indoors: Feb 24 Transplant: Mar 31 🍅 Harvest: Jun 30 – Sep 15
Recommended (50%) ✓ Fits season (36 days to spare)
Start indoors: Mar 2 Transplant: Apr 6 🍅 Harvest: Jul 6 – Sep 21
Safe Start (90%) ✓ Fits season (36 days to spare)
Start indoors: Mar 17 Transplant: Apr 21 🍅 Harvest: Jul 21 – Oct 6

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 Miller County

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

Soil pH

Your soil pH (5.7–6.7) overlaps with Leeks's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Leeks.

Organic Matter

Organic matter is moderate (2.4%). 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
0.6″/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 1.4" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 3.5" 3.4" 0.1" 💧 Light watering
May 3.5" 4.2" 0" ✅ Rainfall sufficient
Jun 3.5" 3.6" 0" ✅ Rainfall sufficient
Jul 3.5" 3.1" 0.4" 💧 Light watering
Aug 3.5" 3.1" 0.4" 💧 Light watering
Sep 3.5" 3.1" 0.4" 💧 Light watering
Oct 3.5" 2.4" 1.1" 💧 Light watering
Nov 1.8" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Miller 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 ~2,010 GDD — county provides 3,417 GDD Excellent fit

Leeks Planting Timeline — Miller County, MO

Leeks Planting Calendar

Activity When Date Range
Start Indoors March 2 Mar 2 – Mar 16
Transplant Outdoors April 6 Apr 6 – Apr 20
Direct Sow March 23 Mar 23 – Apr 13
Harvest July 6 Jul 6 – Sep 21
Fall Sowing August 18 Aug 18 – Sep 1

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors Direct Sow
April Transplant Outdoors Direct Sow
May
June
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 6b

📆 Growing Season

204 days in Miller County

Growing Tips for Leeks in Miller County

Direct sow Leeks outdoors after April 06 in Miller 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 Miller County, MO?

Miller County is in Zone 6b with an average last frost of April 6. Plan your Leeks planting based on this frost date — see the calendar above for exact timing.

What planting zone is Miller County, MO?

Miller County, Missouri is in USDA Hardiness Zone 6b. The average last spring frost is April 6 and first fall frost is October 27.

🌱

Your Miller County Garden Planner — Free

A 24-page printable planner built for Miller County (Zone 6b). 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 Miller County, MO. 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.