When to Plant Garlic in Iowa
Plant in fall, harvest in summer. Garlic is one of the most rewarding crops for the patient gardener.
The Short Answer
Iowa Frost Dates
Your planting dates depend on which part of Iowa you're in. Here are the frost date ranges by region:
| Region | Zones | Last Frost (Spring) | First Frost (Fall) |
|---|---|---|---|
| Northern Iowa | 4b, 5a | May 5 - May 20 | Sep 20 - Oct 5 |
| Central Iowa | 5a, 5b | Apr 25 - May 10 | Oct 1 - Oct 15 |
| Southern Iowa | 5b | Apr 20 - May 5 | Oct 5 - Oct 20 |
Garlic Planting Schedule for Iowa
Northern Iowa (Zones 4b, 5a)
Average last frost: May 5 - May 20 · Average first frost: Sep 20 - Oct 5
Central Iowa (Zones 5a, 5b)
Average last frost: Apr 25 - May 10 · Average first frost: Oct 1 - Oct 15
Southern Iowa (Zones 5b)
Average last frost: Apr 20 - May 5 · Average first frost: Oct 5 - Oct 20
Growing Garlic in Iowa
Garlic in Iowa's Climate
Your cold winters are garlic's secret weapon. Hardneck varieties — the type with the best flavor and those coveted scapes — actually require prolonged cold (vernalization) to form proper bulbs. Plant cloves in October, 6 weeks before the ground freezes, and mulch heavily. The cloves root before winter, sleep under snow, and explode with growth in spring. Northern gardeners grow the best garlic in America because the cold is an asset, not a limitation.
Soil Considerations for Iowa
Outstanding black prairie soils. Some of the richest agricultural land in the world. Minimal amendment needed. Loose, well-drained soil is especially important for garlic since the edible portion grows underground. If your soil is heavy clay, consider raised beds.
Iowa Climate & Growing Season
Continental climate. Cold winters, warm humid summers. Good growing season with adequate rainfall. Garlic can handle frost well, which is an advantage in Iowa's climate. You can push planting dates earlier in spring and extend into fall.
Growing season length varies across Iowa: Northern Iowa (4b, 5a) has a last frost around May 5 - May 20, while Southern Iowa (5b) sees frost end around Apr 20 - May 5. This difference matters for garlic — adjust your planting dates to match your specific region.
Growing Tips
Plant individual cloves pointy-side up in fall, 4-6 weeks before ground freezes. Mulch heavily. Harvest when lower leaves brown.
Companion Planting
Plant garlic alongside these companions for better growth:
Keep garlic away from:
The Bottom Line
Last reviewed: March 29, 2026