Lawn Care Guide for Umatilla County
Umatilla County, Oregon
Data Story
About Lawn Care in Umatilla County, Oregon
High-Heat Lawn Challenges
Umatilla County faces a difficult lawn environment with a score of 30.5. In this Zone 7a climate, conditions are significantly more demanding than the national median of 50.0.
Summer Heat and Dry Air
With 38 extreme heat days per year and only 15.2 inches of rain, grass is under constant stress. The 2,693 growing degree days provide a long season for growth, but only if you can provide enough water.
Unknown Ground Quality
Specific soil pH and texture data are unavailable for Umatilla County at this time. We recommend testing your soil to ensure it meets the ideal 6.0 to 7.0 pH range for nutrient absorption.
Severe Drought Conditions
Over 55% of the county is in severe drought, part of a 42-week dry streak. Focus on water conservation by using mulch in garden beds and letting your lawn go dormant if water restrictions tighten.
Hardy Varieties for Umatilla
Look for heat-hardy Tall Fescue or Kentucky bluegrass to handle the Zone 7a extremes. Seeding is best done after the last frost on April 26 to give the lawn a strong start before the July heat.
Lawn Difficulty Score
Recommended Grasses
Bermudagrass
Cynodon dactylon
Buffalograss
Bouteloua dactyloides
Blue Grama
Bouteloua gracilis
Tall Fescue
Festuca arundinacea
Climate Snapshot
Annual Precip
15.2"
Growing Degree Days
2,693.31
Base 50F
Last Spring Frost
04/26
First Fall Frost
10/16
Days Above 95F
38
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
2.5"
inches of water
Monthly Water
7,804
gallons
Estimated Monthly Cost
$62.43
at $0.008/gallon average
Estimates based on 15" annual precipitation and estimated evapotranspiration. Actual costs vary by local water rates.
Common Lawn Problems in Umatilla County
Drought Stress
With only 15 inches of annual rainfall, lawns in Umatilla County face significant drought stress. Consider drought-tolerant grass species and deep, infrequent watering.
Persistent Drought Conditions
Umatilla County experienced drought conditions for 42 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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