How to read a guaranteed analysis without getting lost

A guaranteed analysis can look like a wall of percentages. But a few principles make any label readable, and help you compare products fairly.

w/w versus w/v

Weight-for-weight (% w/w) expresses nutrient mass as a share of product mass. Weight-for-volume (% w/v) expresses it per unit of volume, which depends on density. Liquid products are often dosed by volume, so w/v is what you'll calculate field rates from — but always compare like with like.

Chelated and complexed micronutrients

Micronutrients such as iron, manganese and zinc are often chelated (with EDTA, EDDHA, EDDHSA) or complexed (with gluconic or heptagluconic acids). The chelating agent protects the metal from locking up in the soil and determines the pH range over which it stays available. For basic soils, EDDHA ortho-ortho iron is the workhorse; for foliar correction, EDTA or organic complexes are common.

pH and density

A product's pH and stability range tell you how it behaves in your tank and soil. Density lets you convert between weight and volume. Together they decide compatibility in a mix.

When in doubt, ask for the technical sheet and a jar test before scaling up.