When to plant tomatoes in Montana

Plant out in Billings

May 11–May 25

Across Montana the window opens between May 11 and June 20. Find your city below; the dates follow each town's own average last frost.

Start indoors, Billings: Mar 9–Mar 23
Plant out, Billings: May 11–May 25
Last sowing for a harvest: Jun 30
Last frost, Billings: May 4

Start seeds indoors 6–8 weeks before the last frost; plant out 1–3 weeks after the last frost. Wait for nights that stay above 50°F. A cold snap after transplanting stalls tomatoes for weeks.

Tomatoes planting dates by city

Start indoorsPlant outSow outdoorsFall plantingAverage last and first frost

JanFebMarAprMayJunJulAugSepOctNovDec

BillingsMay 11–May 25

MissoulaMay 17–May 31

Great FallsMay 13–May 27

BozemanJun 2–Jun 16

Butte-Silver BowJun 20–Jul 4

HelenaMay 16–May 30

KalispellJun 7–Jun 21

In Butte-Silver Bow the frost-free season is shorter than tomatoes need. Start plants indoors and pick early varieties.

Questions

When should I plant tomatoes in Montana?

In Billings, plant out from May 11 to May 25. Across Montana the window opens between May 11 and June 20, depending on the local last frost.

How is this date worked out?

Start seeds indoors 6–8 weeks before the last frost; plant out 1–3 weeks after the last frost. Frost dates are NOAA 1991–2020 averages for the weather station nearest each city.

Is the season long enough for tomatoes everywhere in Montana?

Not quite. In Butte-Silver Bow the frost-free season is shorter than the time tomatoes need to ripen. Start plants indoors and pick an early variety.