Lawn Care Guide for St. Louis County
St. Louis County, Missouri
Data Story
About Lawn Care in St. Louis County, Missouri
Standard Missouri Growing Conditions
St. Louis County sits right at the state average with a lawn difficulty score of 63.5. This Zone 7a region offers a balanced environment for homeowners looking to maintain a traditional green space.
High Heat Requires Diligent Mowing
With 44 extreme heat days, the county is significantly hotter than the state average. Mowing at a higher setting during the summer is critical to protecting the grass crowns from the 79.4°F July average temperatures.
Well-Drained Loam for Healthy Lawns
The county features well-drained silt loam soil with a respectable pH of 6.25. This soil structure is ideal for grass, as it holds onto the 42.1 inches of annual rain without becoming waterlogged or overly compacted.
Managing Seasonal Water Stress
Despite 22 weeks of drought last year, the county remains 100.0% abnormally dry. Deep watering once or twice a week is more effective for these conditions than light daily sprinkling, as it encourages deeper roots.
Take Advantage of an Early Spring
The last frost typically occurs by April 4, allowing for an early start to the seeding season. Utilize the 4,372 growing degree days to establish a robust lawn before the October 29 frost arrives.
Lawn Difficulty Score
Recommended Grasses
Tall Fescue
Festuca arundinacea
Bermudagrass
Cynodon dactylon
Climate Snapshot
Annual Precip
42.1"
Growing Degree Days
4,372.333
Base 50F
Last Spring Frost
04/04
First Fall Frost
10/29
Days Above 95F
44
Hardiness Zone
7a
Seeding Calendar — Zone 7A
Seasonal Lawn Care Checklist
Spring
- Apply pre-emergent herbicide when soil reaches 55F
- Begin mowing when grass reaches 3 inches
- 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
- Overseed warm-season lawns if thinning
- Apply fall fertilizer (highest N application for cool-season)
- Continue mowing until growth stops
- Rake or mulch leaves to prevent smothering
Winter
- Apply pre-emergent for winter weeds
- Service mower and sharpen blades
- Plan spring soil amendments based on fall test
- Keep lawn clear of debris
Watering Deficit Calculator
Monthly Deficit
0.5"
inches of water
Monthly Water
1,482
gallons
Estimated Monthly Cost
$11.85
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 St. Louis County
Persistent Drought Conditions
St. Louis County experienced drought conditions for 22 of the past 52 weeks. Prioritize water-efficient grasses and consider reducing lawn area.
Learn more about regional lawn challenges at The Lawn Report.
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.
Explore more data for St. Louis County