When to plant garlic in Iowa
Iowa’s average last spring frost is April 25, and the first fall frost typically arrives around October 8 — about 166 frost-free days (USDA zones 4b, 5a, 5b). Garlic needs 240–270 days to mature, which is tight for a full-season planting there — see the note below.
When to plant garlic in Iowa: the short answer
For a spring planting, sow Oct 19 – Nov 5. Seeds germinate in soil from 32 to 75°F.
Windows are ~1–2 week bands around each date. Frost dates are a statewide average from NOAA/NCEI normals; your town may differ by two weeks or more. Calendar year 2026.
How to grow garlic in Iowa, step by step
- Prepare the bed. It needs at least six to eight hours of direct sun a day and loose soil at least 12 inches deep, with a pH between 5.5 and 7.5. Dig in compost before planting.
- Water and feed. Give it steady, even moisture, about an inch of water a week from rain or the hose.
- Watch for pests and problems. Pests: onion maggot, onion thrips, stem nematode. Diseases and disorders: white rot, rust, basal rot.
- Harvest. Garlic takes 240-270 days to reach harvest. Plant cloves 2-4 weeks after the first fall frost, pointy end up, and mulch. Hardneck types need this cold period; softneck types suit mild-winter regions and braid well. Harvest the following summer when the lower leaves brown.
Figures come from our crop data; dates use Iowa’s average frost dates. More in the full garlic growing guide.
Garlic planting dates by USDA zone in Iowa
Iowa spans USDA zones 4b, 5a, 5b. Colder zones, usually higher or further inland, have a later last spring frost and an earlier first fall frost than the state average, so the garlic dates shift with them.
When to plant garlic in nearby states
Questions gardeners in Iowa ask
When is the best time to plant garlic in Iowa?
Plant garlic in Iowa between October 19 and November 5. That timing is set for fall, after Iowa's first frost (about October 8).
When will fall-planted garlic be ready in Iowa?
The following June to July. Garlic roots in fall, rests over winter and finishes in early summer - harvest when the lower leaves turn brown.
When is the last frost in Iowa?
On average around April 25, with the first fall frost around October 8 - about 166 frost-free days. Your town may differ by two weeks or more.