Lawn Care Guide for Sullivan County
Sullivan County, New Hampshire
USDA SSURGO / PHZMData Story
About Lawn Care in Sullivan County, New Hampshire
Sullivan County Nears State Average Difficulty
With a lawn difficulty score of 47.3, Sullivan County is nearly on par with the New Hampshire average of 47.9. This USDA Hardiness Zone 5b area offers a slightly more forgiving environment than some neighboring coastal counties. While still below the national median of 50.0, it presents a balanced challenge for local homeowners.
Cooler Summers Benefit Cool-Season Grass
The county enjoys a milder summer with only 6 extreme heat days, staying below the state average of 7. Annual precipitation reaches 42.0 inches, providing consistent natural irrigation for the 2,021 growing degree days. This combination allows for a steady growth cycle without the intense heat stress found in southern regions.
Acidic Soil Demands Regular Testing
Sullivan County soil has a pH of 4.72, which is acidic enough to limit nutrient uptake in most standard turfgrasses. The soil is composed of 36.6% sand and a low 5.3% clay, suggesting that while it drains well, it may struggle to hold onto fertilizers. Adding lime is a critical step to bring the ground closer to the ideal 6.0-7.0 pH range.
Managing Moderate Drought Vulnerability
The area spent 36 weeks in drought over the past year, with 46.1% of the county currently in a severe drought stage. While 100% of the county is abnormally dry, these conditions are less widespread than in other parts of the state. Maintaining a higher mowing height can help shade the soil and retain what little moisture is available.
Plan Around a Shorter Season
Hardy cool-season grasses like Fine Fescue and Ryegrass thrive in Sullivan County's cooler 5b climate. Wait until the last frost passes around May 14th before you begin your spring seeding. With the first fall frost typically hitting by October 1st, the growing window is brief but productive.
Lawn Difficulty Score
Top Grass Fit for Sullivan County
Excellent match
Pennington Smart Seed Sun & Shade
Pennington
Top cultivar score: 86/100
Estimated — county soil data incomplete.
Zone 5b vs Tall Fescue's 3–8 band.
Soil pH 4.71986978919033 vs Tall Fescue's 5.5–6.5 window.
Precipitation 41.95" + soil AWC vs Tall Fescue's 20–30" need.
Growing-degree-days + frost window vs a beginner-difficulty establishment.
Pennington Smart Seed Sun & Shade is the best value in the cool-season grass seed market. Period. You get a quality fescue/KBG blend with genuine drought tolerance coating at a price point significantly below premium options like BBU or Barenbrug RTF.
In Sullivan County, USDA zone 5b, soil pH 4.7, Pennington Smart Seed Sun & Shade scores 86/100 — a strong zone match, adequate moisture, and a long enough establishment window.
Why we ruled these out
- Scotts Turf Builder Bermudagrass — USDA zone 5b is below Scotts Turf Builder Bermudagrass's effective range (6–11); not recommended for this county.
See our fit-score methodology for how survivability is determined.
Recommended Grasses
Tall Fescue
Festuca arundinacea
Climate Snapshot
Annual Precip
42.0"
Growing Degree Days
2,021.4
Base 50F
Last Spring Frost
05/14
First Fall Frost
10/01
Days Above 95F
6
Hardiness Zone
5b
Seeding Calendar — Zone 5B
Seasonal Lawn Care Checklist
Spring
- Apply pre-emergent herbicide when soil reaches 55F
- Overseed bare spots once frost risk passes
- Start irrigation if rainfall is below 1 inch/week
- Soil test every 2-3 years — adjust lime or sulfur as needed
Summer
- Mow at recommended height weekly
- Water deeply 1-2 times per week (1 inch total)
- Avoid fertilizing cool-season grasses in peak heat
- Scout for grubs and treat if >10 per sq ft
Fall
- Core aerate compacted areas
- Apply fall fertilizer (highest N application for cool-season)
- Continue mowing until growth stops
- Rake or mulch leaves to prevent smothering
Winter
- Avoid walking on frozen turf
- Service mower and sharpen blades
- Plan spring soil amendments based on fall test
- Keep lawn clear of debris
Watering Deficit Calculator
Monthly Deficit
0.2"
inches of water
Monthly Water
507
gallons
Estimated Monthly Cost
$4.06
at $0.008/gallon average
Estimates based on 42" annual precipitation and estimated evapotranspiration. Actual costs vary by local water rates.
Common Lawn Problems in Sullivan County
Acidic Soil
Soil pH of 4.7 is below the ideal range for most grasses (6.0-7.0). Apply agricultural lime to raise pH gradually.
Persistent Drought Conditions
Sullivan County experienced drought conditions for 36 of the past 52 weeks. Prioritize water-efficient grasses and consider reducing lawn area.
Learn more about regional lawn challenges at The Lawn Report.
Lawn Care Advisory: Sullivan County
Lawn Verdict
Sullivan County sits in USDA hardiness zone 5b, a transitional zone where cool-season grasses dominate but some warm-season varieties can survive. with winter lows reaching around -15.0°F. though only 2,021.4 growing degree days favor cool-season varieties like Kentucky bluegrass and fescue. Moderate rainfall (42.0 inches) generally supports healthy lawns with minimal supplemental watering.
Seasonal Breakdown
Wait until after May 14 to seed or overseed; soil temperatures should consistently reach 50-55°F. Cool summers (July averages 68.3°F) reduce heat stress — maintain regular mowing and moderate watering. Aerate and overseed cool-season lawns by early fall, well before October 1; this is the best renovation window. Winters are harsh (January averages 19.2°F); avoid foot traffic on frozen turf and plan snow mold prevention.
Watering Guidance
With 42.0 inches of annual rainfall, established lawns typically need watering only during extended dry spells. Currently, 100.0% of the county is in abnormally dry according to the US Drought Monitor. Cool summers reduce water demand; overwatering is a bigger risk than drought stress.
Regional Context
Sullivan County is close to the New Hampshire average temperature, it is somewhat drier than the state average, USDA zone 5b helps guide grass selection compared to neighboring counties.
Want detailed soil composition, drainage classes, and soil series data? View soil details on SoilByCounty.com
Frequently Asked Questions
What USDA hardiness zone is Sullivan County in?
What is the best grass for Sullivan County?
How much rainfall does Sullivan County get?
What is the soil pH in Sullivan County?
Data sourced from USDA SSURGO, NOAA Climate Normals (1991-2020), USDA Plant Hardiness Zone Map, and US Drought Monitor. Lawn difficulty scores and grass recommendations are estimates for informational purposes only.
Explore more data for Sullivan County