HS Codes for Micronutrient Fertilizers: A Buyer's Reference

How an HS code is built: six digits universal, the rest national

The Harmonized System is the World Customs Organization's (WCO) product-naming standard, and its first six digits are internationally harmonized. A code reads chapter, heading, subheading: for copper sulphate, Chapter 28 (inorganic chemicals) → heading 2833 (sulphates) → subheading 2833.25 (of copper). Any country that has adopted the HS reads those six digits the same way, which is why the six-digit code is what you use to query global trade data and to describe goods to a supplier or freight forwarder.

What varies is everything after the sixth digit. Countries extend the code for their own duty rates, statistics and controls: the United States uses 10 digits (HTS), the European Union uses an 8-digit Combined Nomenclature, and other markets append their own national digits. So zinc sulphate is 2833.29 everywhere at six digits, but the United States writes it 2833.29.45.00, and other markets attach their own tail. The practical rule for buyers: agree the six-digit code with your supplier, then confirm the exact 8-to-10-digit line and duty with a licensed broker in the importing country.

The nine product categories and their six-digit codes

The sulphate salts cluster in heading 2833. Magnesium sulphate is 2833.21 and copper sulphate is 2833.25, each with its own subheading. Zinc, manganese and ferrous (iron) sulphate share the residual subheading 2833.29, "other sulphates," at the six-digit level. Boron sources split across two headings: boric acid sits in 2810.00 (oxides of boron; boric acids), while borax — disodium tetraborate — sits in heading 2840, at 2840.19 for the refined hydrated grades (decahydrate and pentahydrate) and 2840.11 for the anhydrous form.

Water-soluble NPK that carries all three of nitrogen, phosphorus and potassium is 3105.20. Chelates are the fiddliest: the EDTA acid and its simple salts are organic chemicals in 2922.49 (oxygen-function amino-compounds), whereas a finished EDTA-chelated micronutrient preparation that contains no N, P or K cannot be entered as an "other fertiliser" and is commonly classified as a chemical preparation in 3824.99 — though customs rulings have also placed single-compound metal chelates in Chapter 29, so confirm this one with a broker before filing. The next section explains the distinction. Treat every code here as the correct starting point for the six-digit level and verify the national tail before you file.

The Chapter 28 vs Chapter 31 line: the classic error

The single most common mistake with these products is assuming that anything sold as a "fertilizer" belongs in Chapter 31 (fertilisers). It does not. Zinc, manganese, iron, copper and magnesium sulphates are separate chemically defined compounds, and the HS classifies them in Chapter 28 (inorganic chemicals) — heading 2833 — even when the intended use is agricultural micronutrition. A drum of zinc sulphate monohydrate is 2833.29, not a Chapter 31 fertilizer.

The reason is a specific legal note. For heading 3105, WCO Chapter 31 Note 6 restricts the term "other fertilisers" to products used as fertilizers that contain, as an essential constituent, at least one of nitrogen, phosphorus or potassium. A pure micronutrient — boron, zinc, manganese, iron, copper — has none of those three elements, so it cannot ride in 3105 on its own. Two nuances prove the rule rather than break it. First, ammonium sulphate and potassium sulphate are sulphates, yet the legal notes claim them for Chapter 31 by name (Notes 2 and 4 to Chapter 31), and Chapter 28 Note 3(c) pushes those goods out of the inorganic-chemicals chapter — precisely because they deliver nitrogen and potassium. Second, a blended product used as a fertilizer that contains N, P or K as an essential constituent — for example an NPK base carrying added micronutrients — can stay in Chapter 31. Get the boundary wrong and you risk a reclassification, a duty adjustment and a delayed clearance.

Where chelates, packaging and hydration trip buyers up

Beyond the 28-versus-31 line, a few details cause repeat problems:

• EDTA, three ways. The EDTA acid and its simple salts are 2922.49. A formulated micronutrient chelate preparation with no N/P/K is commonly entered under 3824.99, but customs rulings have also placed single-compound metal chelates in Chapter 29 — a U.S. ruling classified an iron EDDHA chelate under heading 2922 — so verify the specific product before filing. Only a product carrying N, P or K as an essential constituent can move into Chapter 31 (3105.90, "other"). Do not default a metal-EDTA micronutrient to 3105.
• The national tail matters. Because 2833.29 is a catch-all at six digits, national tariffs split it into product-specific lines — the US Harmonized Tariff Schedule gives zinc sulphate its own line, 2833.29.45.00 — and the duty rate can differ line by line. Same product, different national code and duty per market: another reason to confirm with a broker.
• Anhydrous vs hydrated borax. Refined borax decahydrate and pentahydrate are 2840.19; anhydrous disodium tetraborate is 2840.11. State the water of crystallization on your paperwork so it matches the code.
• Small-package rule. Genuine Chapter 31 fertilizers put up in tablets or similar forms, or in packages of 10 kg gross or less, are drawn into heading 3105 — a rule that applies to fertilizers, not to the Chapter 28 chemicals above.

The customs document package

The HS code drives duty and admissibility, but a clean clearance needs the supporting paperwork. For these products a typical export file includes:

• Commercial invoice and packing list — description, HS code, quantity, value and Incoterm (RunziChem quotes FOB Qingdao).
• Bill of Lading (B/L) or sea waybill, or an Air Waybill for air freight — the transport contract and title document.
• Certificate of Analysis (COA) — the batch assay; for these products the guaranteed content is confirmed per lot on the COA rather than as a fixed figure.
• Certificate of Origin (CO) — standard or a preferential form where a trade agreement lowers duty in the destination market.
• Safety Data Sheet (SDS) and Technical Data Sheet (TDS) in GHS format.
• Third-party inspection reports (for example SGS) when the buyer or letter of credit requires them.

Two frequent questions. First, dangerous goods: many of these inorganic salts and borates ship as general cargo, but not all — copper sulphate, for example, is commonly declared under the IMDG Code as UN 3077, Class 9 (environmentally hazardous substance, marine pollutant) — so confirm the transport classification for each product and grade with your supplier and forwarder. Second, plant-health rules: wooden pallets must be ISPM 15 treated and marked, even though the mineral cargo itself generally needs no phytosanitary certificate — confirm the destination's requirements. An import permit or fertilizer registration, where the destination requires one, is a separate matter handled locally — see below.

Disclaimer and how RunziChem supports the file

This reference is general orientation for procurement and logistics teams, not legal, customs or tariff advice. HS classification turns on the exact composition, grade and form of the goods and on the importing country's current tariff and rulings, which change over time. Always confirm the precise 8-to-10-digit code, duty and any import controls with a licensed customs broker or the customs authority in the destination market before you file.

RunziChem's role is to supply the documentation package — commercial invoice, packing list, batch COA, TDS, SDS, certificate of origin and, on request, third-party inspection reports — so your clearance and any local product registration have the technical evidence they need. Import permits and fertilizer registration are completed by the buyer or a local entity, because those approvals are issued to the importer of record in-country; RunziChem provides the dossier that supports them, not the registration itself.