When to Plant Leeks in Jasper 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.
Jasper County, Iowa is in USDA Zone 5a. The average last spring frost is May 2 and the first fall frost is October 7, giving you a growing season of approximately 158 days.
At an elevation of 1,048 feet, Jasper County receives approximately 38 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Leeks during the growing season.
Jasper County Soil Profile
Soil Type
Silt Loam
Soil pH
6-6.7
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.
Plant Water Budget
Leeks Planting Timeline — Jasper County, IA
Leeks Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 28 | Mar 28 – Apr 11 |
| Transplant Outdoors | May 2 | May 2 – May 16 |
| Direct Sow | April 18 | Apr 18 – May 9 |
| Fall Sowing | July 29 | Jul 29 – Aug 12 |
| Harvest | August 1 | Aug 1 – Oct 17 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Fall Sowing |
| August | Fall Sowing Harvest |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
Sun
Full Sun (6-8+ hours)
Water
Moderate — regular watering
Days to Maturity
90–150 days
Soil pH
6 – 7
USDA Zone
Zone 5a
Growing Season
158 days
Growing Tips for Jasper County
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 Jasper County, IA?
Jasper County is in Zone 5a with an average last frost of May 2. Plan your Leeks planting based on this frost date — see the calendar above for exact timing.
What planting zone is Jasper County, IA?
Jasper County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is May 2 and first fall frost is October 7.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Jasper County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.
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