Lawn Care Guide for Clarke County
Clarke County, Iowa
Data Story
About Lawn Care in Clarke County, Iowa
Clarke Leads the State in Ease
Clarke County boasts an impressive lawn difficulty score of 83.1, making it one of the easiest places in Iowa to grow grass. This score far exceeds the state average of 77.2 and the national baseline of 50.0. The warmer 5b Hardiness Zone offers a slightly longer window for lawn establishment than northern Iowa.
High Energy and High Heat
The climate produces 3233 growing degree days, signaling a very active growing season that requires frequent mowing. While the 38.7 inches of rain is excellent, the county faces 25 extreme heat days, which is much higher than the state average of 16. Grass here needs extra hydration during July to survive those punishing 90°F afternoons.
Heavy Clay and Poor Drainage
Clarke's silty clay loam soil is characterized by poor drainage and a 28.1% clay content. While this helps keep the 6.24 pH soil moist during heat waves, it can lead to waterlogging and root rot during heavy rains. Incorporating gypsum or organic matter can help break up the heavy clay and improve the soil's structure.
Staying Green Through Dry Spells
Though 100% of the county is currently abnormally dry, it only suffered 2 weeks of drought over the past year. This historical resilience suggests that Clarke County lawns are generally well-hydrated. Keep mower blades sharp and high to shade the soil and reduce water loss during the current dry trend.
Maximize the 5b Growing Season
Heat-tolerant Kentucky Bluegrass cultivars or Turf-Type Tall Fescues are ideal for managing the 25 heat days this county experiences. Start your spring planting after April 29 and wrap up fall chores by October 9. The slightly warmer 5b climate allows for strong root establishment if you seed in early September.
Lawn Difficulty Score
Soil Summary
pH
6.2
Texture
Silty clay loam
Drainage
Poorly drained
Organic Matter
3.0%
Recommended Grasses
Tall Fescue
Festuca arundinacea
Climate Snapshot
Annual Precip
38.7"
Growing Degree Days
3,233.1
Base 50F
Last Spring Frost
04/29
First Fall Frost
10/09
Days Above 95F
25
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
0.6"
inches of water
Monthly Water
1,968
gallons
Estimated Monthly Cost
$15.74
at $0.008/gallon average
Estimates based on 39" annual precipitation and estimated evapotranspiration. Actual costs vary by local water rates.
Want detailed soil composition, drainage classes, and soil series data? View soil details on SoilByCounty.com
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.
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