Zinc Sulphate Mono-hydrate (ZnSO4.H2O)
A micronutrient fertiliser specified under the Fertiliser Control Order, 1985 (Schedule I, Part A, 1(g), item 9). Key notified values: Zinc 33.0 min; Sulphate Sulphur 15.0 min.
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Specification
As notified in the Order, line by line. Values are per cent by weight unless the line says otherwise.
How to read this table
- Minimum means the product must contain at least this much; maximum means not more than this (moisture, impurities and heavy metals have a maximum).
- Per cent by weight means grams in every 100 g of product: 0.5 per cent zinc is 5 g of zinc in every kg.
- Tolerance: a lab result may fall slightly short of the notified value before the sample is called non-standard; the limits are in Schedule I, Part B.
- S.O. … (E) is the number of the Gazette notification that made a change; “in force” (w.e.f., with effect from) is the date it started to apply.
| Parameter | Notified value | |
|---|---|---|
| (i) | Free flowing powder form | |
| (ii) | Zinc (as Zn) per cent by weight, minimum | 33.0 |
| (iii) | Sulphate Sulphur (as S) per cent by weight, minimum | 15.0 |
| (iv) | Matter-insoluble in water per cent by weight, maximum | 1.0 |
| (v) | pH (5% solution) not less than | 4.0 |
| (viii) | Cadmium (as Cd) per cent by weight, maximum | 0.0025 |
| (ix) | Arsenic (as As) per cent by weight, maximum | 0.01 |
Note for all micronutrient fertilisers (S.O. 4477(E), 22 Sep 2022): The Micronutrient Mixture grades are made by physically mixing of above specified fertilizers or grades.
Tolerance: how far a sample may fall short of a declared value is set in Schedule I, Part B; see the tolerance limits.
Test methods (Schedule II, Part B): method 7: Zinc sulphate (heptahydrate and monohydrate); method 8: Zinc sulphate, alternate method.
Check a lab report
Compare the results of a lab test with this specification, line by line, including the tolerance allowed in Part B. Enter each result as on the report (per cent by weight unless the line says otherwise). A guide only: the report of a notified laboratory decides whether a sample is standard.
| Parameter | Notified | Lab result | Result |
|---|---|---|---|
| (ii) Zinc | 33.0 mintolerance 0.5 units | ||
| (iii) Sulphate Sulphur | 15.0 mintolerance 0.5 units | ||
| (iv) Matter-insoluble in water | 1.0 max | ||
| (v) pH (5% solution) not less than | 4.0 min | ||
| (viii) Cadmium | 0.0025 max | ||
| (ix) Arsenic | 0.01 max |
Not checked here: Free flowing powder form.
Notification history
- 6 Feb 2017S.O. 349(E): Schedule I, Part A substituted as a whole, with this entry
- 13 Jul 2020S.O. 2324(E): a line omitted (it read: “(vii) Lead (as Pb) per cent. by weight, maximum 0.003”)
- 3 Dec 2025S.O. 5575(E): a line omitted (it read: “(vi) Iron (as Fe) per cent. by weight, maximum 1.0”)
Before you make, label or buy it
- Manufacturers and importers: each declared value on the label must meet the limit above; samples are tested by the notified method.
- Dealers and farmers: check that the product name and declared contents on the pack match this specification, and keep the bill with the batch number.
- Doses are not part of this specification: follow the label and local agricultural advice.
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Consolidated by NanoKheti from the Fertiliser (Inorganic, Organic or Mixed) (Control) Order, 1985, as amended up to the Ninth Amendment Order, 2026 (S.O. 4045(E), 22 Jul 2026), for reference. The Gazette text is authoritative; this page is not legal advice. Check the notification before labelling, licensing or buying. Checked for later changes on 20 October 2026.