PlantAlong

When to plant garlic in zone 6b

Plant for fall between Oct 29 and Nov 5. That is 1-2 weeks after zone 6b's median first frost, Oct 221. Across most of zone 6b that date falls between Oct 17 and Nov 12.

Why a range: zone 6b is defined by winter lows, not frost dates. Its ZIP codes have median first frosts from Oct 10 to Oct 292, so a single zone date can be weeks off for you. The rule comes from University of Wisconsin–Madison Division of Extension, Wisconsin Horticulture, written for WI and applied here to zone 6b's frost dates.

Last reviewed
Stations
899
ZIP codes
4,372
Photo: Chris F / Pexels
These dates use the typical last frost for the whole zone. Your ZIP code gives a closer answer.
  1. Plant for fallWisconsin
  • Start indoors
  • Plant outdoors
  • Range across the zone
  • Frost-free season (median)
  • Spring frost risk (90% to 10%)
  • Fall frost risk (10% to 90%)
Figure 1. Garlic in zone 6b. Dark bars: at the zone's median frost dates. Pale bars: across most of the zone's ZIP codes. Hatched blue: where the zone's last and first frosts fall.
Fall planting
Oct 291-2 weeks after first frost

Five digits. The calendar is computed on your device.

What each source says, applied to zone 6b

The same frost dates give different answers depending on whose rule you follow. These are all the published rules we hold for garlic, worked out at zone 6b's median frost dates.

Table 1. Garlic rules from every source, at zone 6b's median last frost (Apr 22) and first frost (Oct 22).
SourceWhatRuleZone 6b median
Minnesota3Plant for fall1-2 weeks after first frostOct 29 – Nov 5
Wisconsin1Used abovePlant for fall1-2 weeks after first frostOct 29 – Nov 5
Texas A&M (E-502)4Plant for fall4-6 weeks before first frostSep 10 – Sep 24

Frost across zone 6b

  1. Last spring frostmedian Apr 22
  2. First fall frostmedian Oct 22
  • Frost-free season (median)
Figure 2. Frost dates across zone 6b, from 899 NOAA stations matched to 4,372 ZIP codes.

Sources

  1. University of Wisconsin–Madison Division of Extension, Wisconsin Horticulture, Garlic, Allium sativum, Rev: 10/2023. Retrieved 2026-11-02.
  2. NOAA National Centers for Environmental Information, U.S. Climate Normals 2020: U.S. Annual/Seasonal Climate Normals (1991-2020), 2021. Retrieved 2026-11-02.
  3. University of Minnesota Extension, Fruit and Vegetable News blog, Tips for garlic planting season, Page shows October 15, 2026; URL path says 2021/10 (unresolved). Retrieved 2026-11-02.
  4. Texas AgriLife Extension Service, The Texas A&M System, Texas Home Vegetable Gardening Guide (E-502), 2/09. Retrieved 2026-11-02.