Lawn Care Guide for Coos County
Coos County, Oregon
Data Story
About Lawn Care in Coos County, Oregon
Moderate Coastal Maintenance in Coos
Coos County has a lawn difficulty score of 37.4, which sits close to the Oregon state average. The maritime influence of Zone 9a keeps temperatures stable, but the high moisture levels require specific management strategies.
Low Heat Stress and High Humidity
With only 3 days of extreme heat and 60.6 inches of rain, your lawn rarely suffers from scorching. The 1,747 growing degree days indicate a slower, more manageable growth rate compared to inland counties with higher summer temperatures.
Amending Highly Acidic Coastal Soil
A soil pH of 4.71 is quite low, meaning most turf grasses will struggle to absorb phosphorus and magnesium. The soil contains 32.0% sand, which aids drainage but may require organic compost to help hold nutrients against the 60+ inches of rain.
Watching the Abnormal Dryness
Currently, 99.0% of the county is considered abnormally dry despite only 25 weeks of drought last year. To conserve water, avoid over-watering in the morning; instead, rely on the coastal humidity to keep the grass blades from wilting.
Early Start in a Mild Climate
Fine Fescues and Colonial Bentgrass are ideal for this cool, damp coastal environment. Because the last frost is typically as early as March 21, you have a long window to establish your lawn before the summer peak.
Lawn Difficulty Score
Recommended Grasses
Bermudagrass
Cynodon dactylon
Climate Snapshot
Annual Precip
60.6"
Growing Degree Days
1,746.62
Base 50F
Last Spring Frost
03/21
First Fall Frost
11/14
Days Above 95F
3
Hardiness Zone
9a
Seeding Calendar — Zone 9A
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
- Raise mowing height to reduce heat stress
- 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
- Overseed with ryegrass for winter color
Watering Deficit Calculator
Monthly Deficit
0.0"
inches of water
Monthly Water
0
gallons
Estimated Monthly Cost
$0.00
at $0.008/gallon average
Estimates based on 61" annual precipitation and estimated evapotranspiration. Actual costs vary by local water rates.
Common Lawn Problems in Coos County
Excess Moisture & Fungal Disease
High annual rainfall (61 inches) increases risk of fungal diseases like brown patch and dollar spot. Ensure good drainage and avoid overwatering.
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
Coos County experienced drought conditions for 25 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.
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