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When to plant Leeks in Appleton City, MO

Plant Leeks in Appleton City, when soil hits 50°F — usually March 25. Continue planting through April 15 for the spring crop. A second sowing from August 17 to August 31 extends the harvest into fall.

When to Plant Leeks in Appleton City, MO

Leeks
St. Clair County, Missouri Zone 6b June

Your June gardening checklist

Your St. Clair County, Missouri garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost April 8
Avg. first frost October 26
Soil temp (4") 73°F
Watering Low
Pest pressure High
Daylight 14.6 hrs
To set up a strong July, finish these tasks
  • First harvests: leeks

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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.

Appleton City, Missouri is in USDA Zone 6b. The average last spring frost is April 8 and the first fall frost is October 26, giving you a growing season of approximately 201 days.

At an elevation of 699 feet, St. Clair County receives approximately 41.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Leeks during the growing season.

Appleton City, MO (Zone 6b) Long season
201 days
Last Spring Frost April 8
201 growing days
First Fall Frost October 26

Appleton City Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.7

Drainage

Well Drained

Leeks Planting Risk Windows

Early Start (70% safe) ✓ Fits season (33 days to spare)
Start indoors: Feb 25 Transplant: Apr 1 🍅 Harvest: Jul 1 – Sep 16
Recommended (50%) ✓ Fits season (33 days to spare)
Start indoors: Mar 4 Transplant: Apr 8 🍅 Harvest: Jul 8 – Sep 23
Safe Start (90%) ✓ Fits season (33 days to spare)
Start indoors: Mar 15 Transplant: Apr 19 🍅 Harvest: Jul 19 – Oct 4

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 Appleton City

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

Soil pH

Your soil pH (5.5–6.7) overlaps with Leeks's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in St. Clair 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 (2.9%). 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.

Leeks Water Budget

Plant needs
0.8″/week
Rainfall provides
0.9″/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 1.7" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 3.5" 4.3" 0" ✅ Rainfall sufficient
May 3.5" 5.2" 0" ✅ Rainfall sufficient
Jun 3.5" 4.8" 0" ✅ Rainfall sufficient
Jul 3.5" 4.8" 0" ✅ Rainfall sufficient
Aug 3.5" 4.2" 0" ✅ Rainfall sufficient
Sep 3.5" 3.9" 0" ✅ Rainfall sufficient
Oct 3.5" 3.1" 0.4" 💧 Light watering
Nov 2.9" 0" ❄️ Dormant
Dec 2.3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in St. Clair 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 ~2,100 GDD — county provides 3,517 GDD Excellent fit

Leeks Planting Timeline — Appleton City, MO

Leeks Planting Calendar

Activity When Date Range
Start Indoors March 4 Mar 4 – Mar 18
Transplant Outdoors April 8 Apr 8 – Apr 22
Direct Sow March 25 Mar 25 – Apr 15
Harvest July 8 Jul 8 – Sep 23
Fall Sowing August 17 Aug 17 – Aug 31

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 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

201 days in St. Clair County

Growing Tips for Leeks in Appleton City

Direct sow Leeks outdoors after April 08 in St. Clair 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 →

When should I plant Leeks in Appleton City, MO?

In Appleton City, MO, plant Leeks after the last frost (around April 8) and before the first frost (around October 26). Best results when soil holds above 50°F.

What growing zone is Appleton City, MO for Leeks?

Appleton City sits in USDA Zone 6b. Leeks grows reliably in zones 3a through 10b, so it's a good fit here.

Can Leeks grow in Appleton City's climate?

Yes — Leeks grows well in Appleton City's temperate climate. Appleton City averages a 201-day frost-free season, with last frost around April 8 and first frost around October 26.

🌱

Your St. Clair County Garden Planner — Free

A 22-page printable planner built for St. Clair 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.

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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. Clair County, MO. Local conditions may vary. Last updated: June 2026.