Sonnette 7 SW, MT Lawn Care Calendar

Every timing-sensitive lawn job in Sonnette 7 SW, timed to the local climate record — not a national average.

Turf region
Cool-season
Kentucky bluegrass, tall fescue, perennial ryegrass, fine fescue
Last spring frost
May 25
median, 1991–2020
First fall frost
Sep 19
median, 1991–2020
Growing stretch
117 days
frost to frost
TaskSonnette 7 SW windowWhy then
Crabgrass pre-emergent May 4 – May 25 Soil nearing 55°F — must beat germination
Light spring feeding May 25 – Jun 22 After green-up, before summer stress
Aerate + overseed Jul 21 – Aug 5 Fall growth surge; established before cold
Main fall feeding Jul 25 – Aug 22 The year’s most important nitrogen
Winterizer feeding Aug 22 – Sep 5 Root reserves for spring green-up
Final mow Sep 12 – Oct 3 Growth stops around first frost

Anchored to NOAA 1991–2020 climate normals at the SONNETTE 7 SW station. Windows are estimates — soil temperature is the real trigger, especially for pre-emergent. Check your own ZIP with the lawn calendar lookup.

Sonnette 7 SW lawn care, month by month

MonthTasks
January Dormant — keep leaves cleared, stay off frozen turf
February Dormant — keep leaves cleared, stay off frozen turf
March Dormant — keep leaves cleared, stay off frozen turf
April Dormant — keep leaves cleared, stay off frozen turf
May Apply crabgrass pre-emergent · Light feeding after green-up
June Light feeding after green-up
July Aerate + overseed · Main fall feeding
August Aerate + overseed · Main fall feeding · Winterizer feeding
September Winterizer feeding · Final mow of the year
October Final mow of the year
November Dormant — keep leaves cleared, stay off frozen turf
December Dormant — keep leaves cleared, stay off frozen turf

Reading the Sonnette 7 SW lawn year

Sonnette 7 SW runs on the classic northern rhythm: a short, important spring (pre-emergent before soil hits 55°F, one light feeding), a defensive summer (mow tall, water deep, feed nothing), and then the season that actually builds a lawn — early fall, when aeration, overseeding around Jul 21 – Aug 5, and the year's main feeding all land before the Sep 19 frost closes the year. With only ~117 frost-free days, the fall window is tight — miss it and the next real chance is spring.

Grasses that fit Sonnette 7 SW

Frequently asked questions

When should I overseed my lawn in Sonnette 7 SW?

For cool-season grass (bluegrass, fescue, ryegrass), overseed in early fall — in Sonnette 7 SW that means roughly Jul 21 – Aug 5, timed 45–60 days before the average first fall frost (Sep 19) so seedlings establish before cold. Spring works as a backup but collides with crabgrass season.

When do I put down crabgrass preventer in Sonnette 7 SW?

Aim for May 4 – May 25 — the estimated stretch when Sonnette 7 SW soil approaches the ~55°F germination threshold, anchored to the average last frost (May 25). It's an estimate: a soil thermometer reading 50–55°F at 2″ depth for several days is the precise trigger, and pre-emergent must go down before crabgrass sprouts, not after.

When should I stop mowing in Sonnette 7 SW?

Keep mowing as long as the grass grows — in Sonnette 7 SW that's typically until Sep 12 – Oct 3, around the average first fall frost (Sep 19). Take the final cut slightly shorter to discourage snow mold.

What grass grows best in Sonnette 7 SW?

Montana is cool-season country: Kentucky bluegrass, tall fescue, perennial ryegrass, fine fescue. See the grass guides linked below for identification and care.