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When to Plant Garlic in Hardin County, IA

Garlic is a pungent allium planted in fall and harvested the following summer. Hardneck varieties produce edible flower stalks (scapes) and are more cold-hardy.

Hardin County, Iowa is in USDA Zone 4b. The average last spring frost is April 28 and the first fall frost is October 9, giving you a growing season of approximately 164 days.

At an elevation of 507 feet, Hardin County receives approximately 40.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Garlic to ensure they mature before fall.

Hardin County, IA (Zone 4b) Moderate season
164 days
Last Spring Frost April 28
164 growing days
First Fall Frost October 9

Hardin County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (17 days to spare)
Transplant: Apr 22 🍅 Harvest: Jul 22 – Sep 16
Recommended (50%) ✓ Fits season (17 days to spare)
Transplant: Apr 28 🍅 Harvest: Jul 28 – Sep 22
Safe Start (90%) ✓ Fits season (13 days to spare)
Transplant: May 11 🍅 Harvest: Aug 10 – Oct 5

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

Plant needs
1.0″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Garlic needs ~2,021 GDD — county provides 2,009 GDD Tight fit

Garlic Planting Timeline โ€” Hardin County, IA

Garlic Planting Calendar

Activity When Date Range
Fall Sowing August 28 Aug 28 โ€“ Sep 11

Plant 1" deep ยท 6" apart ยท Rows 12" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May โ€”
June โ€”
July โ€”
August Fall Sowing
September Fall Sowing
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

90โ€“240 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 4b

Growing Season

164 days

Growing Tips for Hardin County

Plant individual cloves pointed end up in fall, 6 weeks before ground freezes. Mulch heavily with straw. Harvest when lower leaves begin to brown but 5-6 green leaves remain.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans
  • Asparagus

Level Up Your Garden

Frequently Asked Questions

When should I plant Garlic in Hardin County, IA?

Hardin County is in Zone 4b with an average last frost of April 28. Plan your Garlic planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Hardin County, IA?

Hardin County, Iowa is in USDA Hardiness Zone 4b. The average last spring frost is April 28 and first fall frost is October 9.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Hardin County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.

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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 Hardin County, IA. Local conditions may vary. Last updated: April 2026.