When to Plant Leeks in Sac County, IA
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.
Sac County, Iowa is in USDA Zone 4b. The average last spring frost is April 25 and the first fall frost is October 8, giving you a growing season of approximately 166 days.
At an elevation of 1,221 feet, Sac County receives approximately 31.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Leeks to ensure they mature before fall.
Sac County Soil Profile
Soil Type
Silt Loam
Soil pH
5.9-6.7
Drainage
Well Drained
Plant 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 Sac County
How your county's soil matches Leeks's growing requirements.
Soil pH
Your soil pH (5.9–6.7) overlaps with Leeks's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Sac County is excellent for Leeks — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.8%) — Leeks will thrive.
How to Plant Leeks
Fall planting: Sow 12 weeks before your first frost date for a fall harvest.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Leeks Planting Timeline — Sac County, IA
Leeks Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 14 | Mar 14 – Mar 28 |
| Transplant Outdoors | April 25 | Apr 25 – May 9 |
| Direct Sow | April 18 | Apr 18 – May 9 |
| Fall Sowing | July 16 | Jul 16 – Jul 30 |
| Harvest | July 25 | Jul 25 – Sep 19 |
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 Direct Sow |
| June | — |
| July | Fall Sowing Harvest |
| August | Harvest |
| September | 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 4b
📆 Growing Season
166 days in Sac County
Growing Tips for Leeks in Sac County
Direct sow Leeks outdoors after April 25 in Sac 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
Level Up Your Garden
Leeks in Other Locations
Frequently Asked Questions
When should I plant Leeks in Sac County, IA?
Sac County is in Zone 4b with an average last frost of April 25. Plan your Leeks planting based on this frost date — see the calendar above for exact timing.
What planting zone is Sac County, IA?
Sac County, Iowa is in USDA Hardiness Zone 4b. The average last spring frost is April 25 and first fall frost is October 8.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Sac County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.
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