Product Quality & Specifications

A fertilizer specification sheet is the only document that lets you compare two suppliers meaningfully. This page explains how to read one, and what we provide.

What we document

Every product in our range has a specification covering the guaranteed analysis, physical form, solubility and handling notes. The figures shown on our product pages are indicative of the standard grade — the current specification sheet is the authoritative document, and we send it on request before you order.

Where a product has grade variants, we will tell you which variant a quotation refers to. A price is meaningless without knowing which grade it applies to.

How to read a specification

1. Check what the percentage actually refers to

Nutrient content can be expressed as the element (Fe, K, Mg) or as the oxide (K₂O, MgO, P₂O₅). These are not the same number. 50% K₂O is about 41.5% elemental potassium. Comparing an oxide figure with an elemental figure will make one product look considerably better than it is. Our guide to NPK ratios explains the conversions.

2. Look for the fraction that does the work

Total content is not always the useful number:

• For Fe-EDDHA, the ortho-ortho isomer percentage matters more than total iron. Two products at 6% Fe can perform very differently.
• For amino acid products, free amino acid content matters more than total, and the L-form fraction determines whether the plant can use it at all.
• For humic products, the split between humic and fulvic acids matters, along with whether the figure is quoted on a dry or as-supplied basis.

3. Check solubility and insoluble matter

For anything going through a drip system, insoluble residue is a maintenance cost. A cheaper soluble NPK that leaves residue in the filter is not cheaper once you count the labour and the emitters.

4. Check the physical form

Granular, prilled, crystalline and powder grades of the same chemical behave differently in storage, dissolving and dust generation. Several products are hygroscopic and must stay sealed.

What we do not publish

We do not display certifications, accreditations or quality marks on this site. Where a specific certificate or document is required for your market or your own quality system, ask us during the quotation stage and we will confirm in writing what can be provided for that product and shipment. We would rather answer that question accurately per order than publish a claim you cannot verify.

Ask for the documentation

Request the specification for any product before ordering. If you are running a formal supplier evaluation, our guide on how to evaluate a fertilizer supplier lists the questions worth asking us and everyone else on your list.