Nutrient salts in a foliar feed
Eleven nutrient salts appear across the range. What each supplies, why a naturally derived product contains them, and where the labelling needs to be more careful.
Why this page exists
A grower reading the ingredient list of a plant-nutrition product will find mono-potassium phosphate, potassium sulfate, magnesium sulfate, calcium chloride and a series of micronutrient sulfates. These are manufactured mineral salts. A reasonable question follows: how does that sit with a product range positioned around natural and low-residue inputs?
The honest answer is that plant nutrition is elemental. A plant takes up potassium as the potassium ion regardless of whether it came from a mined sulfate, a composted banana or a seaweed extract. There is no natural or synthetic version of a potassium ion. Where natural sourcing genuinely matters — pesticidal actives, residues on produce, effects on soil biology and non-target organisms — it matters a great deal. For mineral nutrients it matters much less, and claiming otherwise would be misleading.
What does differ between nutrient sources is counter-ion, solubility, salt index, pH effect and any organic fraction that comes along with it. Those are real and worth understanding.
The salts in the range
Mono-potassium phosphate — phosphorus and potassium, highly soluble, mildly acidic, low salt index. The most widely used salt in the range.
Potassium sulfate and potassium chloride — both supply potassium; the counter-ion is the decision. Sulfate adds sulfur and suits chloride-sensitive crops; chloride is cheaper but chloride-sensitive crops including many fruits, potatoes and tobacco can be damaged. Note the data issue flagged elsewhere: Potassium Pro lists potassium chloride as the active and potassium sulfate as the derived-from source. Those are not the same thing and the discrepancy matters agronomically.
Potassium nitrate — potassium plus nitrate nitrogen, in NPK Pro.
Calcium chloride — highly soluble calcium, used where calcium mobility is the limiting factor as in blossom-end rot and bitter pit. Chloride again warrants attention.
Magnesium sulfate — magnesium and sulfur, both mobile and readily taken up.
Manganese, zinc and copper sulfates, boric acid and ammonium molybdate — the micronutrient sources. Copper deserves a specific note: copper accumulates in soil and does not degrade, so repeated application over years is a genuine long-term consideration rather than a nutritional non-issue.
Phosphoric acid — phosphorus and strong acidification, useful for adjusting alkaline spray water.
A labelling issue to fix
The crop product pages carry a templated FAQ line describing each product as a naturally derived input, generated by interpolating the active field. On urea and synthetic salt formulations that produces statements such as "a naturally derived input (Urea, manganese sulfate, EDTA-Fe + citric acid)". Urea and EDTA chelates are not naturally derived. That claim needs to be scoped to the products where it is accurate — and this page is the right place to explain the distinction properly.
Reading a fertiliser label
Guaranteed analysis gives the elemental percentages. Derived-from tells you the salts, and therefore the counter-ions, the salt index and the pH behaviour. Both matter, and the second is the one most often ignored.