Billings, MT · zone 4b · ~149 frost-free days
When to plant in Billings: frost dates and zone 4b.
In Billings, the typical last spring frost lands around May 7 and the first fall frost around Oct 3, giving you about 149 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 Billings, keyed to your frost.
| Crop | Start indoors | Spring sow / set out | Fall sow |
|---|---|---|---|
| Tomato, slicing | Apr 2 to May 27 | May 14 to Jul 8 | — |
| Lettuce, leaf | — | Mar 30 to May 14 | Jul 20 to Sep 18 |
| Carrot | — | Mar 30 to May 2 | Jul 8 to Aug 3 |
| Bush Bean | — | May 7 to Jun 27 | — |
| Cucumber, slicing | — | May 14 to Jul 17 | — |
| Pepper, bell | Apr 11 to May 30 | May 23 to Jul 11 | — |
| Kale | Feb 16 to Mar 16 | Mar 30 to Apr 27 | Jul 3 to Aug 18 |
| Spinach | — | Mar 16 to Apr 27 | Jul 20 to Sep 7 |
Billings sits in Zone 4b, 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 Billings 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 59101 in about 60 seconds.
Billings planting questions
What planting zone is Billings, MT?+
Billings is in USDA hardiness zone 4b. Growing zone, gardening zone, and planting zone all mean the same thing: the USDA number, 4b 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 Billings?+
The typical last spring frost in Billings, MT is around May 7. 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 Billings?+
The typical first fall frost in Billings, MT arrives around Oct 3, closing a growing season of roughly 149 frost-free days. Count backward from it to find the last date a fall crop can still finish.
What can I plant now in Billings?+
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 7. The table above shows each crop's window; the free planner turns your ZIP into an exact, dated calendar.