Plant biostimulants under EU rules and the CE marking route

In the EU, plant biostimulants stimulate plant nutrition processes independently of the product's nutrient content. Their sole aim must be to improve one or more characteristics of the plant or the plant rhizosphere: nutrient use efficiency, tolerance to abiotic stress, quality traits, or availability of confined nutrients in the soil or rhizosphere. This is the definition in PFC 6 of the EU Fertilising Products Regulation.

Meeting that definition does not establish CE compliance. Under Regulation (EU) 2019/1009, a product on the EU CE route must also meet component-material, safety, efficacy, labelling and conformity-assessment requirements before it is placed on the Union market as an EU fertilising product. That includes a product a UK or US company places on the Union market. Article 4 requires the Annex I function rules, the Annex II material rules and the Annex III label. Conformity assessment is in Annex IV, not in Article 4.

What is a biostimulant under EU law?

The legal definition is about function. A general promise of better plant growth is not enough. PFC 6, the plant biostimulant product function category, permits the four aims listed above.

A product may target more than one effect. But it must deliver the effects claimed on its label for the plants specified there. Recognition of the category does not prove that a particular formulation works. These requirements appear in Annex I, Part II, PFC 6(1) and (4).

Biostimulants and fertilisers

The phrase "biostimulant fertilizer" can blur nutrient supply and stimulation of nutrition processes. PFC 6 requires the stimulation to act independently of the product's nutrient content. It does not require a biostimulant to contain no nutrients. Nutrient content alone is not the deciding test. Assess the claimed function against the PFC 6 definition.

Plant growth stimulants and protection claims

"Plant growth stimulants" is not a safe legal synonym for PFC 6. The definition is narrower than any effect on growth. Tolerance to abiotic stress does not justify claims about preventing disease or protecting plants against harmful organisms. Article 1(1)(b) excludes plant protection products from this Regulation. Annex III, Part I, point 8(d) bars claims, by statements or visual representations, that a fertilising product prevents or treats plant diseases or protects plants against harmful organisms. Check the pictures too. A review that stops at the written label can miss that point.

Microbial and non-microbial plant biostimulants

Product function categories (PFCs) describe what a product does. Component material categories (CMCs) govern the materials it contains. A listed material still needs the claimed PFC 6 function, and a suitable function still needs eligible materials. Both sets of requirements apply under Article 4.

PFC 6(A) covers microbial plant biostimulants consisting of a microorganism or consortium referred to in CMC 7. PFC 6(B) covers plant biostimulants other than microbial biostimulants. And a non-microbial classification does not remove the need for a lawful component-material route. Annexes I and II have to be read together.

The CMC 7 list in the latest consolidation identified by EUR-Lex, dated 1 July 2026, has four entries. These are list entries, not four individual species. See CMC 7 and the EUR-Lex consolidation record.

• Azotobacter spp.
• Mycorrhizal fungi.
• Rhizobium spp.
• Azospirillum spp.

Don't assume that Bacillus, Pseudomonas or Trichoderma qualify through CMC 7. They are absent from that list. Their absence limits this CE route and does not prove a worldwide or national prohibition. The FPR's harmonised route is optional, as recital 5 explains.

CMC 7 can include dead or empty-cell microorganisms and non-harmful residual production-media elements under its conditions. Its processing condition is precise: microorganisms must "have undergone no other processing than drying or freeze-drying". That wording does not require actual drying. Check the formulation and production process against CMC 7 itself.

Preparing a plant biostimulant for CE marking

Treat classification as the start of the compliance work. The sequence below covers the main decisions. It is not every requirement for a particular formulation.

Establish the function and eligible materials

Define the claimed effect and the target plants. Map the formulation to the relevant CMC requirements, then show compliance with the applicable product and material rules. The label claims must match the product's effects for the plants named. Article 4 and Annex I, PFC 6 require these separate checks.

Prepare the label

PFC 6 label information has to include the items below. They sit on top of the general rules for a fertilising-product label.

• Physical form.
• Production and expiry date.
• Application method or methods.
• Effect claimed for each target plant.
• Any relevant instructions on efficacy, including soil management practices, chemical fertilisation, incompatibility with plant protection products, recommended spraying nozzle size, sprayer pressure and other anti-drift measures.

General requirements also cover quantity, application rates, timing, frequency, storage and relevant risk information. The destination Member State decides the language end-users must be able to understand, so an English-only label is not automatically sufficient (the exporter's home office does not decide this). See Annex III and Articles 6(7) and 8(4).

Microbial products must identify intentionally added microorganisms, with strains where applicable, and state their concentration in relevant active units. They must also carry this warning: "Micro-organisms may have the potential to provoke sensitising reactions". These are additional PFC 6(A) label duties.

Select the conformity-assessment route

Module A internal production control is unavailable for PFC 6. Module B followed by Module C is available only for a product composed solely of component materials listed in Annex IV, Part I, point 3.1. Module D1 is available for PFC 6 under Annex IV, Part I, point 4.1. Both routes involve a notified body, but the assessment tasks differ. Not every formulation can use B+C. Annex IV governs route selection.

Prepare the technical documentation and complete the applicable assessment. Then draw up the EU declaration of conformity and affix CE before placing the product on the market. CE marking is not a blanket product approval from a regulator. It follows the manufacturer's duties in Articles 6(2) and 18.

Whether the CE marking is followed by a notified-body number depends on the route. Under D1, the CE marking is followed by the relevant notified body's identification number. Under Module C following B, the Module B body's number is not required beside CE. Article 18(3), Module D1 point 7.1 and Module C point 3.1 make this distinction.

Account for the EU importer

UK and US exporters must account for the EU-established importer and its duties. Article 2(13) defines an importer as any natural or legal person established within the Union who places an EU fertilising product from a third country on the Union market. Review those duties in Article 8, next to the manufacturer's obligations.

CE harmonisation is optional. National-law routes remain possible under the relevant national rules. They are not an exemption from all regulation, and they do not give automatic EU-wide CE access. Recital 5 keeps compliance with the harmonised rules optional for products that are not CE marked. Article 1(1) applies this Regulation to EU fertilising products. Article 2(2) defines an EU fertilising product as a fertilising product which is CE marked when made available on the market.

Organic claims and markets outside the EU

CE or PFC 6 status does not establish suitability for organic farming. Neither a microbial formulation nor a natural origin makes "organic biostimulants" an automatic category. Check the separate input rules in Implementing Regulation (EU) 2021/1165.

EU status also does not establish UK or US compliance. In the US, intended plant-regulator uses fall within the pesticide definition in 40 CFR 152.3. Qualifying plant nutrients, plant inoculants and soil amendments have exclusions only when intended solely to aid desirable plant growth, under 40 CFR 152.6(g). PFC 6 status alone does not establish that exclusion.

RegAffairs AI's answer on EU plant biostimulants covers the definition and CE-marking requirements.