PlantAlong

When to plant garlic in zone 8a

Plant for fall between Nov 13 and Nov 20. That is 1-2 weeks after zone 8a's median first frost, Nov 61. Across most of zone 8a that date falls between Nov 7 and Nov 28.

Why a range: zone 8a is defined by winter lows, not frost dates. Its ZIP codes have median first frosts from Oct 31 to Nov 142, 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 8a's frost dates.

Last reviewed
Stations
650
ZIP codes
2,528
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 8a. 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
Nov 131-2 weeks after first frost

Five digits. The calendar is computed on your device.

What each source says, applied to zone 8a

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 8a's median frost dates.

Table 1. Garlic rules from every source, at zone 8a's median last frost (Mar 29) and first frost (Nov 6).
SourceWhatRuleZone 8a median
Minnesota3Plant for fall1-2 weeks after first frostNov 13 – Nov 20
Wisconsin1Used abovePlant for fall1-2 weeks after first frostNov 13 – Nov 20
Texas A&M (E-502)4Plant for fall4-6 weeks before first frostSep 25 – Oct 9

Frost across zone 8a

  1. Last spring frostmedian Mar 29
  2. First fall frostmedian Nov 6
  • Frost-free season (median)
Figure 2. Frost dates across zone 8a, from 650 NOAA stations matched to 2,528 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.