When to plant Leeks in Rombauer, MO
Rombauer sits in USDA Zone 7b. Plant Leeks between March 13 (after last frost on March 27) and April 3. A second sowing from August 24 to September 7 extends the harvest into fall.
When to Plant Leeks in Rombauer, MO
Your June planting checklist for Butler County, Missouri
A quick June briefing for Butler County, Missouri gardeners — what's urgent, what's next, and what can wait.
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Bring in the leeks
Check every 1–2 days. Many of these get tough or go to seed if you wait too long.
A few tasks this June that'll pay off in July
- First harvests: leeks
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.
Rombauer, Missouri is in USDA Zone 7b. The average last spring frost is March 27 and the first fall frost is November 2, giving you a growing season of approximately 220 days.
At an elevation of 703 feet, Butler County receives approximately 36.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Leeks during the growing season.
Rombauer Soil Profile
Soil Type
Silt Loam
Soil pH
5.5-6.6
Drainage
Well Drained
Leeks Planting Risk Windows
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 Rombauer
How your county's soil matches Leeks's growing requirements.
Soil pH
Your soil pH (5.5–6.6) overlaps with Leeks's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Butler 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
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Leeks Water Budget
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 | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.6" | 0" | ❄️ Dormant |
| Mar | 3.5" | 2.5" | 1" | 💧 Light watering |
| Apr | 3.5" | 3.7" | 0" | ✅ Rainfall sufficient |
| May | 3.5" | 4.8" | 0" | ✅ Rainfall sufficient |
| Jun | 3.5" | 4.1" | 0" | ✅ Rainfall sufficient |
| Jul | 3.5" | 3.7" | 0" | ✅ Rainfall sufficient |
| Aug | 3.5" | 3.9" | 0" | ✅ Rainfall sufficient |
| Sep | 3.5" | 3.6" | 0" | ✅ Rainfall sufficient |
| Oct | 3.5" | 3" | 0.5" | 💧 Light watering |
| Nov | 3.5" | 2.3" | 1.2" | 💧 Light watering |
| Dec | — | 2.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Butler 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 Planting Timeline — Rombauer, MO
Leeks Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 20 | Feb 20 – Mar 6 |
| Transplant Outdoors | March 27 | Mar 27 – Apr 10 |
| Direct Sow | March 13 | Mar 13 – Apr 3 |
| Harvest | June 26 | Jun 26 – Sep 11 |
| Fall Sowing | August 24 | Aug 24 – Sep 7 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| 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 · Only during dry spells
📅 Days to Maturity
90–150 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 7b
📆 Growing Season
220 days in Butler County
Growing Tips for Leeks in Rombauer
Direct sow Leeks outdoors after March 27 in Butler 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
Check more plant combinations with our Companion Planting Checker →
Leeks in Other Locations
When should I plant Leeks in Rombauer, MO?
In Rombauer, MO, plant Leeks after the last frost (around March 27) and before the first frost (around November 2). Best results when soil holds above 50°F.
What growing zone is Rombauer, MO for Leeks?
Rombauer sits in USDA Zone 7b. Leeks grows reliably in zones 3a through 10b, so it's a good fit here.
Can Leeks grow in Rombauer's climate?
Yes — Leeks grows well in Rombauer's temperate climate. Rombauer averages a 220-day frost-free season, with last frost around March 27 and first frost around November 2.
Your Butler County Garden Planner — Free
A 22-page printable planner built for Butler 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.