New Hampshire’s climate closely matches neighbouring Vermont and Maine. Cool-season grasses dominate, with Kentucky Bluegrass for sunny areas and Fine Fescue blends for the state’s many shaded, wooded properties.
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Measure My LawnNew Hampshire falls in the north zone (USDA Zone 5), which means cool-season grasses perform best. Here are the most common grass types for New Hampshire lawns:
Also viable: Tall Fescue
Based on Kentucky Bluegrass in the north zone. Spring soil temperatures in New Hampshire average 39°F, meaning your pre-emergent window usually opens in late April or May.
| Month | Key Tasks | Mowing | Water |
|---|---|---|---|
| January | Water Your Lawn | — | — |
| February | Water Your Lawn | — | — |
| March | Apply Pre-Emergent HerbicideMow to 2.5-3.0 InchesSpring Clean-UpSpring FertiliserEnsure 1 Inch Per Week of Water | 2.5-3.0" | 1"/wk |
| April | Mow to 2.5-3.0 InchesPost-Emergent Weed ControlSeed-Safe Weed Prevention (Tenacity)Spring OverseedingEnsure 1 Inch Per Week of Water | 2.5-3.0" | 1"/wk |
| May | Grub Preventive ApplicationMow to 2.5-3.0 InchesEnsure 1 Inch Per Week of Water | 2.5-3.0" | 1"/wk |
| June | Mow to 3.0-3.5 InchesEnsure 1.5 Inches Per Week of Water | 3.0-3.5" | 1.5"/wk |
| July | Mow to 3.0-3.5 InchesSummer Stress ManagementEnsure 2 Inches Per Week of Water | 3.0-3.5" | 1.5"/wk |
| August | Mow to 3.0-3.5 InchesSummer Stress ManagementEnsure 1.5 Inches Per Week of Water | 3.0-3.5" | 1.5"/wk |
| September | Core Aerate Your LawnDethatch Your LawnFall Fertiliser (First Application)Fall OverseedingMow to 2.5-3.0 InchesStarter Fertiliser for Fall OverseedingEnsure 1 Inch Per Week of Water | 2.5-3.0" | 1"/wk |
| October | Fall Fertiliser (Second Application)Mow to 2.5-3.0 InchesPost-Emergent Weed CleanupEnsure 1 Inch Per Week of Water | 2.5-3.0" | 1"/wk |
| November | Mow to 2.5-3.0 InchesEnsure 1 Inch Per Week of WaterWinterizer Fertiliser | 2.5-3.0" | 1"/wk |
| December | Water Your LawnWinter Lawn Care | — | — |
These are the most problematic weeds in the northeast region. Timing your pre-emergent application to soil temperature is the most effective prevention strategy.
Grassy annual · Germinates at 55-65°F soil temp
Broadleaf perennial · Germinates at 40-50°F soil temp
Broadleaf perennial · Germinates at 50-65°F soil temp
Broadleaf annual · Germinates at 40-50°F soil temp
Broadleaf perennial · Germinates at 50-65°F soil temp
Snap a photo and we’ll identify your weed, then give you treatment options for free.
Identify My WeedsSymptoms: Circular patches 6 inches to several feet in diameter with tan, dead grass in the center and a darker brown or purplish border (smoke ring effect). In early stages, affected turf appears water-soaked ...
Prevention: Maintain adequate potassium, avoid excessive nitrogen in warm months, improve air circulation, ensure proper drainage, and water deeply but infrequently in early morning.
Symptoms: Small, tan or straw-colored patches 1–2 inches in diameter (resembling silver dollars, hence the name). In fine-textured turf, lesions appear as dark red or brown bands on individual leaf blades. Patc...
Prevention: Maintain moderate nitrogen levels, reduce thatch, improve drainage and air circulation, avoid overhead watering, and mow at recommended height to reduce humidity within the canopy.
Symptoms: Small, tan or gray lesions with dark red or purple borders on leaf blades. Spots are roughly rectangular and may have a tan, papery center. Severe infections cause leaves to wither; large areas of tur...
Prevention: Use resistant varieties of ryegrass or fescue. Maintain proper mowing height and nitrogen balance. Ensure good drainage and air circulation. Water only soil in early morning.
Symptoms: Small, circular patches (1–4 inches) of pink, bleached, or straw-colored grass. Look closely and you'll see fine pink or reddish threads (fungal threads, called hyphae) extending from grass blades and...
Prevention: Maintain adequate nitrogen levels (2–3 applications yearly). Improve drainage and air circulation. Avoid overhead watering, particularly in cool, wet seasons. Reduce thatch.
With New Hampshire's average spring soil temperature of 39°F, here are the key temperature thresholds that drive your lawn care timing:
| Task | Temp | Direction | Why It Matters |
|---|---|---|---|
| Apply crabgrass pre-emergent (granular) | 55°F | Rising | First spring application when soil reaches 55°F at 4-inch depth |
| Cool-season spring fertiliser | 55°F | Rising | Apply when soil temperature reaches 55°F to stimulate spring growth |
| Grub preventive (GrubEx) | 60°F | Rising | Apply before grub eggs hatch, typically June when soil reaches 60°F |
| Post-emergent broadleaf weed control | 60°F–80°F | Rising | Air temperature critical: avoid application above 85°F (herbicide damage risk) |
| Cool-season dormancy begins | 0°F–45°F | Falling | Grass dormancy when soil consistently below 45°F for extended period |
| Cool-season spring greenup begins | 45°F–50°F | Rising | Cool-season grass emerges from dormancy at 45-50°F soil temp |
| Winterizer fertiliser (cool-season) | 40°F–50°F | Falling | Final fall application at soil temp 40-50°F before full dormancy |
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Take a photo of a single grass blade and compare it to your region's common grasses online, or pull out a small section and show it to your local garden center. The easiest way is to check what your lawn builder or previous owner planted—most lawns in a region have 1–2 standard types.
Spring (when grass first greens up) is ideal because the grass is actively growing and will respond to your care. Fall is the second-best time. You can start anytime, but spring gives fastest visible results.
It's the single best investment for a new lawn manager—a $30 test tells you your pH, nutrient levels, and what fertilizer you actually need. Without it, you're guessing and might waste money. Most universities offer cheap tests through their extension service.
Yes. Most lawn problems improve with correct mowing, watering, and targeted fertilizer within 1–2 seasons. Only bare patches larger than 5 square feet or complete dead zones typically need reseeding or patching.
Mow at the right height for your grass type—this single action solves 40% of lawn problems because taller grass shades weeds, holds water better, and has deeper roots. Fix your mower height before buying anything else.
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