Northampton County Soil Data
Northampton County, Pennsylvania
USDA SSURGO / PHZMAvg pH
4.9
Texture
Gravelly loam
Drainage
Well drained
Organic Matter
6.9%
Hydrologic Group
A
Data Story
About Soil in Northampton County, Pennsylvania
Acidic Alfisols of the Lehigh Valley
Northampton County's soils are primarily Alfisols, known for being productive but relatively acidic with an average pH of 4.88. This is significantly lower than the state average of 5.22 and the national median of 6.5. Alfisols are characterized by a clay-enriched sublayer that can provide a good reservoir for plant nutrients.
Gravelly Loams Offer Quick Workability
The dominant texture is a gravelly loam, featuring 37.6% silt, 27.6% sand, and 14.5% clay. The presence of gravel improves aeration and helps the soil warm up quickly in the spring, though it can make digging more strenuous. This well-balanced texture prevents the soil from becoming too compacted under normal conditions.
Moderate Fertility and Leaner Water Storage
Organic matter in the county averages 6.86%, which is below the Pennsylvania average of 12.14% but still well above the 2.0% national benchmark. Available water capacity is 0.126 in/in, which is lower than the state average of 0.151 in/in. This suggests that Northampton gardens may need more frequent watering during the peak of summer.
Efficient Drainage for Easy Building
Most soils here are classified as well drained and fall into hydrologic group A. This means water moves through the profile quickly, which is excellent for preventing root rot and managing storm water. It also makes the county's land generally favorable for construction and septic systems.
Warm Starts in Zone 7a
Northampton's Zone 7a climate provides an early start to the spring and a late finish to the fall. The well-drained, gravelly soil is perfect for Mediterranean herbs like lavender and rosemary that hate 'wet feet.' With a little extra irrigation and compost, your Northampton garden will be the envy of the neighborhood.
Soil Composition
Soil pH
Soil Series
Detailed soil series data not yet available for this county.
Hydrologic Group
Group A — Low Runoff
Sandy, well-drained soils with high infiltration rates. Water moves quickly through the soil profile. Lowest runoff potential when thoroughly wetted.
Drainage Class
Well drained
Water is removed from the soil readily but not rapidly. Optimal for most plants and construction.
Soil Profile
Dominant texture: Gravelly loam
Typical soil profile. Actual depths vary by location.
USDA Soil Orders
Acidic Soil Detected
Your county's average pH is 4.9. These products help balance soil pH for healthier grass.
Browse Soil AmendmentsFrequently Asked Questions
What type of soil does Northampton County have?
Northampton County's soil is classified as Gravelly loam. This indicates the relative proportions of sand, silt, and clay — 28% sand, 38% silt, and 15% clay. Loamy soils hold moisture well and support a wide range of plants.
Is Northampton County's soil acidic or alkaline?
Northampton County's soil has a low pH of 4.9, which is strongly acidic. Acidic soils benefit from lime applications to raise pH and improve nutrient availability.
What is the drainage class for Northampton County?
Northampton County has a dominant drainage class of "Well drained." Well-drained soils allow excess water to move through quickly, reducing waterlogging risk and supporting most field and garden crops.
What crops or plants grow well in Northampton County's soil?
Based on Northampton County's Gravelly loam texture, pH of 4.9, and Well drained, the soil is well suited for acid-loving plants like blueberries and azaleas, row crops and vegetable gardens, most annual and perennial crops.
What USDA soil order is found in Northampton County?
Northampton County's dominant soil order is Alfisols. Alfisols are moderate to high base-status soils with a clay-enriched subsoil. They support productive forests and cropland across temperate regions.
Soil & Planting Advisory: Northampton County
Soil Verdict
Northampton County is in USDA hardiness zone 7a, a moderate climate zone. where winter lows can reach 0°F. Mild winters mean soil rarely freezes deeply, allowing year-round microbial activity and faster organic matter breakdown.
Planting Guidance
Warm-season crops, citrus relatives, and heat-loving ornamentals do well. Cool-season vegetables should be planted in fall and winter. Winter protection (mulch, burlap wraps) helps push the zone boundary for desired species. Always match plant selections to the specific microclimate of your property — low spots, slopes, and wind exposure can shift effective hardiness by half a zone.
Soil Implications
Warm soils accelerate organic matter breakdown, so compost and mulch need replenishing more frequently than in cooler zones. Sandy soils common in warm zones drain quickly; water-retentive amendments like compost or peat help hold moisture. When soil temperatures drop below freezing, microbial nitrogen cycling stops; spring fertilization is more effective than late-fall application.
Regional Context
Northampton County is somewhat warmer than the Pennsylvania statewide average. The zone range of 6b-7a within the county means soil and planting decisions should account for local elevation and topography.
Planning your lawn? View lawn care data for Northampton County on LawnByCounty.com →
Other Counties in Pennsylvania
Soil data sourced from USDA SSURGO via Soil Data Access. Data is informational only and should not be used as a substitute for on-site soil testing. Contact your local NRCS office for site-specific soil information.