When to plant Leeks in Lucas County, IA
The best window to plant Leeks in Lucas County, is April 7–April 28, when soil warms to 50°F. Last frost typically hits April 21; first frost October 13. A second sowing from August 4 to August 18 extends the harvest into fall.
When to Plant Leeks in Lucas County, IA
August in the garden — Lucas County, Iowa
A quick August briefing for Lucas County, Iowa gardeners — what's urgent, what's next, and what can wait.
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Basket week: leeks
Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.
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Kick off the fall garden with leeks
Count back from your first frost (October 13) — these need to mature before the cold arrives.
September will be here before you know it — start on
- 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.
Lucas County, Iowa is in USDA Zone 5b. The average last spring frost is April 21 and the first fall frost is October 13, giving you a growing season of approximately 175 days.
At an elevation of 638 feet, Lucas County receives approximately 41.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Leeks during the growing season.
Lucas County Soil Profile
Soil Type
Silt Loam
Soil pH
6.3-6.9
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 Lucas County
How your county's soil matches Leeks's growing requirements.
Soil pH
Your soil pH (6.3–6.9) is within Leeks's preferred range (6.0–7.0).
Soil Texture
The silt loam soil in Lucas County is excellent for Leeks — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.9%). 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 | — | 1.9" | 0" | ❄️ Dormant |
| Feb | — | 1.6" | 0" | ❄️ Dormant |
| Mar | — | 3" | 0" | ❄️ Dormant |
| Apr | 3.5" | 3.7" | 0" | ✅ Rainfall sufficient |
| May | 3.5" | 5.2" | 0" | ✅ Rainfall sufficient |
| Jun | 3.5" | 5.3" | 0" | ✅ Rainfall sufficient |
| Jul | 3.5" | 5" | 0" | ✅ Rainfall sufficient |
| Aug | 3.5" | 4.6" | 0" | ✅ Rainfall sufficient |
| Sep | 3.5" | 3.5" | 0" | ✅ Rainfall sufficient |
| Oct | 3.5" | 2.7" | 0.8" | 💧 Light watering |
| Nov | — | 2.9" | 0" | ❄️ Dormant |
| Dec | — | 2.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Lucas 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 — Lucas County, IA
Leeks Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 17 | Mar 17 – Mar 31 |
| Transplant Outdoors | April 21 | Apr 21 – May 5 |
| Direct Sow | April 7 | Apr 7 – Apr 28 |
| Harvest | July 21 | Jul 21 – Oct 6 |
| Fall Sowing | August 4 | Aug 4 – Aug 18 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow |
| May | Transplant Outdoors |
| June | — |
| July | Harvest |
| August | Fall Sowing Harvest |
| September | Harvest |
| October | Harvest |
| 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: ideal
🗺️ USDA Zone
Zone 5b
📆 Growing Season
175 days in Lucas County
Growing Tips for Leeks in Lucas County
Direct sow Leeks outdoors after April 21 in Lucas 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
Frequently Asked Questions
When should I plant Leeks in Lucas County, IA?
Lucas County is in Zone 5b with an average last frost of April 21. Plan your Leeks planting based on this frost date — see the calendar above for exact timing.
What planting zone is Lucas County, IA?
Lucas County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 21 and first fall frost is October 13.
When should I plant Leeks in Lucas County, IA?
In Lucas County, IA, plant Leeks after the last frost (around April 21) and before the first frost (around October 13). Best results when soil holds above 50°F.
What growing zone is Lucas County, IA for Leeks?
Lucas County sits in USDA Zone 5b. Leeks grows reliably in zones 3a through 10b, so it's a good fit here.
Can Leeks grow in Lucas County's climate?
Yes — Leeks grows well in Lucas County's temperate climate. Lucas County averages a 175-day frost-free season, with last frost around April 21 and first frost around October 13.
Your Lucas County Garden Planner — Free
A 22-page printable planner built for Lucas County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.