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When to Plant Garlic in Howard 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.

Howard County, Iowa is in USDA Zone 4b. The average last spring frost is May 4 and the first fall frost is October 5, giving you a growing season of approximately 154 days.

At an elevation of 1,297 feet, Howard County receives approximately 39.7 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.

Howard County, IA (Zone 4b) Moderate season
154 days
Last Spring Frost May 4
154 growing days
First Fall Frost October 5

Howard County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (6 days to spare)
Transplant: Apr 28 🍅 Harvest: Jul 28 – Sep 22
Recommended (50%) ✓ Fits season (7 days to spare)
Transplant: May 4 🍅 Harvest: Aug 3 – Sep 28
Safe Start (90%) ✓ Fits season (6 days to spare)
Transplant: May 16 🍅 Harvest: Aug 15 – Oct 10

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
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Garlic needs ~2,021 GDD — county provides 1,886 GDD Tight fit

Garlic Planting Timeline โ€” Howard County, IA

Garlic Planting Calendar

Activity When Date Range
Fall Sowing August 24 Aug 24 โ€“ Sep 7

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

154 days

Growing Tips for Howard 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 Howard County, IA?

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

What planting zone is Howard County, IA?

Howard County, Iowa is in USDA Hardiness Zone 4b. The average last spring frost is May 4 and first fall frost is October 5.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Howard 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 Howard County, IA. Local conditions may vary. Last updated: April 2026.