PlantAlong

When to plant garlic in zone 5b

Plant for fall between Oct 18 and Oct 25. That is 1-2 weeks after zone 5b's median first frost, Oct 111. Across most of zone 5b that date falls between Oct 8 and Nov 2.

Why a range: zone 5b is defined by winter lows, not frost dates. Its ZIP codes have median first frosts from Oct 1 to Oct 192, 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 5b's frost dates.

Last reviewed
Stations
687
ZIP codes
2,445
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 5b. 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 181-2 weeks after first frost

Five digits. The calendar is computed on your device.

What each source says, applied to zone 5b

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 5b's median frost dates.

Table 1. Garlic rules from every source, at zone 5b's median last frost (May 1) and first frost (Oct 11).
SourceWhatRuleZone 5b median
Minnesota3Plant for fall1-2 weeks after first frostOct 18 – Oct 25
Wisconsin1Used abovePlant for fall1-2 weeks after first frostOct 18 – Oct 25
Texas A&M (E-502)4Plant for fall4-6 weeks before first frostAug 30 – Sep 13

Frost across zone 5b

  1. Last spring frostmedian May 1
  2. First fall frostmedian Oct 11
  • Frost-free season (median)
Figure 2. Frost dates across zone 5b, from 687 NOAA stations matched to 2,445 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.