NCDA CS Soil Test Guide, Lime Fertilizer Calculator (PDF Download)

HOW TO READ YOUR NCDA AND CS SOIL TEST REPORT

A 12-page printable guide for North Carolina homeowners. Every field on the report explained in the lab's own words.

THE TEST IS FREE. READING THE REPORT IS NOT.

North Carolina gives residents a soil test at no charge for eight months of the year. Then the report arrives and it is a grid of abbreviations: HM%, W/V, CEC, BS%, Ac, P-I, K-I, Ca%, Mg%, S-I, Mn-I, Zn-I, Cu-I. None of those numbers are parts per million, and none of them mean what they mean on another state's lab report.

Most people glance at the lime recommendation and file the rest. This guide reads the whole thing, field by field.

WHAT IS INSIDE

- Every field on the NCDA and CS report, with what it is and how to read it
- The index scale: why 25 is critical, 50 is sufficient for P and K but 25 is sufficient for sulfur and the micronutrients, and why above 100 is wasted money
- The calcium and magnesium trap: these are percentages of your CEC, not indexes, and are read a completely different way
- The magnesium calculation you can actually run, and how it decides calcitic versus dolomitic lime
- The actual lime equation NCDA and CS publishes, target pH by plant, and the 50 lb per 1,000 sq ft surface cap
- Turning the recommendation into a bag at the store, with both NC-published worked examples
- Sampling: depth, core count, timing, tools to avoid, and the December peak-season fee
- Amending Piedmont clay, including why NC State says not to add sand

WHERE NORTH CAROLINA DISAGREES WITH ITSELF

Two NCDA and CS documents give different core counts and different garden sampling depths. NCDA and CS and NC State give different lime conversion factors. They differ on how often to retest clay. All printed with both positions and a recommendation.

THE LINE THAT SAVES THE MOST MONEY

When P and K levels exceed 50, NCDA and CS recommends only nitrogen. Most Piedmont yards fertilized for years are already there. If yours is, every bag of 10-10-10 is two thirds wasted, and the phosphorus you do not need is the part most likely to end up in a creek.

FORMAT

Instant digital download. One PDF, 12 pages, US Letter, print at home or read on a tablet. No physical item ships.

WHAT THIS IS AND IS NOT

An educational guide compiled from NCDA and CS Agronomic Division and NC State Extension publications, written for the North Carolina Piedmont. Soil test indexes and units are state specific and nothing here transfers to another state's report. Lab fees and peak season dates change, so verify at ncagr.gov before acting. This is not a site-specific recommendation for your property.

Alex Purdy, Carolina Terrain, Waxhaw, North Carolina. NC Landscape Contractor License CL.1872. I am a licensed contractor, not a professional engineer, not a registered landscape architect and not an agronomist. Your county Extension agent will read your report with you at no charge.

If this guide helped, a review helps other North Carolina homeowners find it.