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When to plant Leeks in Linn County County,

Spring Leeks in Linn County County goes in April 11–May 2, once nighttime temps stop dipping near freezing. A second sowing from August 2 to August 16 extends the harvest into fall.

When to Plant Leeks in Linn County, IA

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.

Linn County, Iowa is in USDA Zone 5a. The average last spring frost is April 25 and the first fall frost is October 11, giving you a growing season of approximately 169 days.

At an elevation of 938 feet, Linn County receives approximately 36.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Leeks to ensure they mature before fall.

Linn County, IA (Zone 5a) Moderate season
169 days
Last Spring Frost April 25
169 growing days
First Fall Frost October 11

Linn County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-7.2

Drainage

Well Drained

Monthly Watering Guide for Leeks

Leeks needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Leeks Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 4.3" 3.3" 1" 💧 Light watering
May 4.3" 4.3" 0" ✅ Rainfall sufficient
Jun 4.3" 4.2" 0.1" 💧 Light watering
Jul 4.3" 3.9" 0.4" 💧 Light watering
Aug 4.3" 4.3" 0" ✅ Rainfall sufficient
Sep 4.3" 3.4" 0.9" 💧 Light watering
Oct 4.3" 3" 1.3" 💧 Light watering
Nov 2.7" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Linn County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Leeks Planting Timeline — Linn County, IA

Leeks Planting Calendar

Activity When Date Range
Start Indoors March 21 Mar 21 – Apr 4
Transplant Outdoors April 25 Apr 25 – May 9
Direct Sow April 11 Apr 11 – May 2
Harvest July 25 Jul 25 – Oct 10
Fall Sowing August 2 Aug 2 – Aug 16

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June
July Harvest
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

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 5a

📆 Growing Season

169 days in Linn County

Growing Tips for Linn 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

  • Peas
  • Green Beans

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Leeks in Linn County, IA?

Linn County is in Zone 5a 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 Linn County, IA?

Linn County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 25 and first fall frost is October 11.

When should I plant Leeks in Linn County County, ?

In Linn County County, , plant Leeks after the last frost (around April 25) and before the first frost (around October 11). Best results when soil holds above 50°F.

What growing zone is Linn County County, for Leeks?

Linn County County sits in USDA Zone 5a. Leeks grows reliably in zones 3a through 10b, so it's a good fit here.

Can Leeks grow in Linn County County's climate?

Yes — Leeks grows well in Linn County County's temperate climate. Linn County County averages a 169-day frost-free season, with last frost around April 25 and first frost around October 11.

🌱

Your Linn County Garden Planner — Free

A 22-page printable planner built for Linn County (Zone 5a). 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 Linn County, IA. Local conditions may vary. Last updated: June 2026.

Sources & credits

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