Sun River 4 S lawn care, month by month
| Month | Tasks |
|---|---|
| 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 |
| June | Apply crabgrass pre-emergent · Light feeding after green-up |
| July | Aerate + overseed · Main fall feeding |
| August | Main fall feeding · Winterizer feeding |
| September | Final mow of the year |
| October | Dormant — keep leaves cleared, stay off frozen turf |
| November | Dormant — keep leaves cleared, stay off frozen turf |
| December | Dormant — keep leaves cleared, stay off frozen turf |
Reading the Sun River 4 S lawn year
Sun River 4 S 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 12 – Jul 27, and the year's main feeding all land before the Sep 10 frost closes the year. With only ~100 frost-free days, the fall window is tight — miss it and the next real chance is spring.
Grasses that fit Sun River 4 S
Frequently asked questions
When should I overseed my lawn in Sun River 4 S?
For cool-season grass (bluegrass, fescue, ryegrass), overseed in early fall — in Sun River 4 S that means roughly Jul 12 – Jul 27, timed 45–60 days before the average first fall frost (Sep 10) so seedlings establish before cold. Spring works as a backup but collides with crabgrass season.
When do I put down crabgrass preventer in Sun River 4 S?
Aim for May 12 – Jun 2 — the estimated stretch when Sun River 4 S soil approaches the ~55°F germination threshold, anchored to the average last frost (Jun 2). 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 Sun River 4 S?
Keep mowing as long as the grass grows — in Sun River 4 S that's typically until Sep 3 – Sep 24, around the average first fall frost (Sep 10). Take the final cut slightly shorter to discourage snow mold.
What grass grows best in Sun River 4 S?
Montana is cool-season country: Kentucky bluegrass, tall fescue, perennial ryegrass, fine fescue. See the grass guides linked below for identification and care.