Zone 3b Club · Lawn Calendar
Zone 3b Lawn Calendar
Year-round timing tuned to Zone 3b's climate window.
Winter low
-35°F
Last frost
May 20
First frost
Sep 20
Season
120d
Primary Overseeding Window
Aug 20 → Sep 15
The single highest-leverage window for cool-season seed in Zone 3b.
Quarter
Spring in Zone 3b
- ▪Late May: rake winter damage and overseed thin spots (KBG primary, PRG nurse)
- ▪First mow when grass reaches 4 inches; cut to 3 inches
- ▪Apply 0.5–0.75 lb N/1000 sqft around late May–early June
- ▪Pre-emergent crabgrass at soil temp 55°F (late May)
Quarter
Summer in Zone 3b
- ▪Mow at 3–3.5 inches
- ▪1" water per week including rain; deep + infrequent
- ▪Hold fertilizer in July–August on non-irrigated lawns
- ▪Brown patch is rare here — focus on watering discipline
Quarter
Fall in Zone 3b
- ▪Primary overseeding: Aug 20 – Sep 15 (soil temps 60–70°F)
- ▪Most important fert of the year: 1 lb N/1000 sqft in late August
- ▪Aerate compacted areas before overseed
- ▪Final mow at 2.5 inches by mid-October
Quarter
Winter in Zone 3b
- ▪Lawn dormant under snow
- ▪Avoid traffic on frozen turf — crown damage is permanent
- ▪Plan spring purchases in February
Continue at Premium Grass Seeds
Build the fall window before it opens.
Use the calendar for timing, then move through the three buying decisions in order. Start with the zone-filtered seed comparison, then use the matching starter and equipment guides. The seed comparison stays anchored to Zone 3b.
1 · Seed
Compare zone-fit fall seed
Start with overseeding options that list this zone, then confirm the local establishment window.
Open: Compare zone-fit fall seed → (opens in a new tab)2 · Starter
Pair the starter fertilizer
Pick the establishment feed after the seed; it is not a substitute for it.
Open: Pair the starter fertilizer → (opens in a new tab)3 · Equipment
Stage the overseeding tools
Choose the spreader, prep, and watering gear before the window opens.
Open: Stage the overseeding tools → (opens in a new tab)
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