How to Read Your Soil Report

SSURGO is the most detailed soil survey dataset in the United States, published by the USDA Natural Resources Conservation Service. It maps soil types at the field level — far more precise than county-level estimates or zip code generalizations. Each mapped area (called a "map unit") carries laboratory-tested properties including pH, drainage class, texture, organic matter, and water-holding capacity.

When Growable Ground analyzes your parcel, we query SSURGO data for the exact soil map units that intersect your property boundary. Two neighbors on the same street can have completely different soil map units — and completely different growing potential.

Soil pH measures acidity or alkalinity on a scale from 0 to 14, with 7.0 being neutral. Most garden soils fall between 4.5 and 8.5. This single number controls nutrient availability — iron, phosphorus, manganese, and other elements become locked in the soil at the wrong pH, even when physically present.

Your Growable Ground report shows your parcel's SSURGO-measured pH and scores every plant in our database against it. A blueberry scoring 96 on a pH 4.8 parcel might score 40 on a pH 7.4 parcel three houses away — same plant, completely different viability.

Pro Tip

Before buying amendments, get your Growable Ground report first. Many growers spend money lowering pH when their soil already suits hundreds of productive species. Work with what you have before changing it.

USDA classifies soil drainage into seven classes, from "excessively drained" (water passes through almost immediately) to "very poorly drained" (water sits on the surface for extended periods). Drainage class is determined by soil texture, depth to water table, and landscape position.

• Well drained / Moderately well drained: Suits most vegetables, fruit trees, and herbs. Water moves through the root zone within 24 hours after heavy rain.
• Somewhat poorly drained: Workable with raised beds. Root crops and plants needing dry feet (lavender, rosemary) will struggle in-ground. Berries and some perennials adapt.
• Poorly / Very poorly drained: Waterlogged soils that limit growing to wetland-adapted species — cranberries, wild rice, some native sedges. Raised beds or drainage infrastructure required for conventional gardening.

Growable Ground's crop engine adjusts scores based on drainage. A tomato variety doesn't just need the right pH and sun — it needs drainage that prevents root rot. Our scoring catches these compound interactions.

SSURGO organizes soils into map units, each identified by a code (like "254B" or "Wg"). The letter suffix indicates slope: A is nearly flat (0–3%), B is gentle (3–8%), C is moderate (8–15%), and so on. Steeper slopes affect erosion, water retention, and ease of cultivation.

Each map unit carries a complete soil profile — pH, texture (sand/silt/clay percentages), organic matter, available water capacity, depth to bedrock, and more. Your report pulls these properties directly from the USDA Soil Data Access service for the map units under your parcel.

When your report says "map unit 254B — Bridgewater fine sandy loam, 3 to 8 percent slopes" — that's the USDA's classification for the specific soil at your location, mapped by soil scientists who walked the ground and collected samples.

A soil report tells you where your soil sits on the USDA map and what it measures — pH, drainage class, texture. The soil type is the other half of the story: whether your ground is glacial till, sandy loam, red clay, or drained muck tells you how it got there, how it behaves through a season, and which crops have thrived in it for generations.

We keep a full field guide to every soil type named on our state growing pages — what each one is, how it drains, what thrives in it, and how to work with it: Soil Types Explained →