Zinc Sulphate 21% vs 27% vs 33%: Which Concentration Should You Buy?
All zinc sulphate fertilizers deliver the same nutrient — zinc — but at different concentrations by weight. Our range spans Agro Gold (21% Zn), Saffaron (27% Zn, pentahydrate), and Commander (33% Zn, monohydrate), and the right choice usually comes down to cost per unit of zinc delivered rather than the price of the bag itself.
A higher concentration like 33% means less product is needed to deliver the same amount of actual zinc to the soil, which can lower transport and labour costs on larger holdings. Lower concentrations like 21% spread more material per acre, which some farmers prefer for more even manual broadcasting on smaller plots.
The hydration form also plays a role: monohydrate zinc sulphate (like Commander) is more concentrated and less prone to caking in storage, while pentahydrate forms (like Saffaron) dissolve slightly faster in water, which some growers prefer for tank-mixed foliar applications.
For most rice, wheat, cotton, and vegetable growers correcting a general zinc deficiency, any of the three concentrations will work if the total zinc applied per acre is matched correctly. It's worth comparing price per kilogram of actual zinc, not just price per bag, when deciding between them.