LawnWeather

Montana Lawn Care Calendar

In Montana, crabgrass preventer typically goes down between Apr 30 and Jun 8: first in Billings, last in Bozeman. Below are typical fertilizer, seeding and frost dates for Billings, Missoula, Great Falls, Bozeman and Helena, from 2016–2025 weather data. Enter your ZIP code for this year's timing.

When to apply pre-emergent in Montana

Typically between Apr 30 and Jun 8, depending on where you live. The window opens first in Billings (around Apr 30) and last in Bozeman (around May 11). Apply when soil reaches 50°F, before it stays above 55°F.

CityCrabgrass preventer window
BillingsApr 30 – May 15
Great FallsMay 4 – Jun 5
HelenaMay 7 – Jun 6
MissoulaMay 10 – May 27
BozemanMay 11 – Jun 8

Cool-season lawn calendar

Lawns across Montana are mostly cool-season grass (tall fescue, Kentucky bluegrass, perennial ryegrass).

CitySpring fertilizerOverseeding & seedingFall fertilizer
BillingsMay 8 – Jun 12Jul 31 – Sep 19Aug 20 – Oct 29
MissoulaMay 20 – Jun 24Jul 18 – Sep 6Jul 29 – Oct 17
Great FallsMay 29 – Jul 3Jul 26 – Sep 14Jul 29 – Oct 17
BozemanJun 1 – Jul 6Jul 18 – Sep 6Jul 16 – Oct 17
HelenaMay 30 – Jul 4Jul 20 – Sep 8Jul 16 – Oct 13

Frost dates in Montana

CityLast spring frostFirst fall frost
BillingsApr 30Oct 14
MissoulaMay 9Oct 1
Great FallsMay 6Oct 9
BozemanMay 17Oct 1
HelenaMay 10Oct 3

Median dates, 2016–2025. A dash means frost does not occur in most years.

Frequently asked questions

When should I put down pre-emergent in Montana?

Typically between Apr 30 and Jun 8, depending on where you live. The window opens first in Billings (around Apr 30) and last in Bozeman (around May 11). Apply when soil reaches 50°F, before it stays above 55°F.

When is the best time to seed grass in Montana?

Early fall is best for cool-season grass (tall fescue, Kentucky bluegrass, perennial ryegrass): typically from Jul 18 to Sep 19 across Montana, while soil cools from 65°F toward 50°F.

What type of grass grows in Montana?

Most lawns in Montana are cool-season grass (tall fescue, Kentucky bluegrass, perennial ryegrass).

Lawn care guides

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