Green Bay, WI · zone 5a · ~161 frost-free days
When to plant in Green Bay: frost dates and zone 5a.
In Green Bay, the typical last spring frost lands around May 2 and the first fall frost around Oct 10, giving you about 161 frost-free days. Cool-season crops go out before the last frost; warm-season crops wait until after it.
The 2026 windows
Sow dates for Green Bay, keyed to your frost.
| Crop | Start indoors | Spring sow / set out | Fall sow |
|---|---|---|---|
| Tomato, slicing | Mar 28 to May 28 | May 9 to Jul 9 | — |
| Lettuce, leaf | — | Mar 25 to May 9 | Jul 27 to Sep 25 |
| Carrot | — | Mar 25 to Apr 27 | Jul 15 to Aug 10 |
| Bush Bean | — | May 2 to Jun 22 | Jun 26 to Jul 29 |
| Cucumber, slicing | — | May 9 to Jul 24 | — |
| Pepper, bell | Apr 6 to May 28 | May 18 to Jul 9 | — |
| Kale | Feb 11 to Mar 11 | Mar 25 to Apr 22 | Jul 10 to Aug 25 |
| Spinach | — | Mar 11 to Apr 22 | Jul 27 to Sep 14 |
Green Bay sits in Zone 5a, but two gardens in the same city can be a week or two apart. The planner works from your ZIP code's frost dates, not the zone, so the dates land right for your block, not the metro average.
Build your Green Bay garden plan.
Tell the free planner what you want to eat and who you're feeding. It returns plant counts, spacing, and frost-safe sow dates for ZIP 54301 in about 60 seconds.
Green Bay planting questions
What planting zone is Green Bay, WI?+
Green Bay is in USDA hardiness zone 5a. Growing zone, gardening zone, and planting zone all mean the same thing: the USDA number, 5a here. It tells you what survives winter, not when to plant. Frost dates set your planting time, and the free planner uses your exact ZIP code's frost dates, which can differ by weeks across one metro.
When is the last frost date in Green Bay?+
The typical last spring frost in Green Bay, WI is around May 2. That is an average from local history, not a guarantee, so tender crops like tomatoes and peppers are safer with a week of buffer after it.
When is the first frost date in Green Bay?+
The typical first fall frost in Green Bay, WI arrives around Oct 10, closing a growing season of roughly 161 frost-free days. Count backward from it to find the last date a fall crop can still finish.
What can I plant now in Green Bay?+
It depends on the date. Cool-season crops like lettuce, kale, and spinach go out weeks before the last frost; warm-season crops like tomatoes and peppers wait until after May 2. The table above shows each crop's window; the free planner turns your ZIP into an exact, dated calendar.