Which claim fits my plant biostimulant?

A plant biostimulant stimulates plant nutrition processes. Its claimed effect must be independent of its own nutrient content. Simply feeding the plant is not enough to establish a biostimulant effect.

These are illustrative questions and measurements. They are not ready-to-use label claims or a prescribed method list. Select methods that fit the product and claim.

Customer experience and scientific information about the ingredients can help identify a promising effect. Small exploratory tests can help you decide what to investigate.

These are useful starting points, but they do not replace the evidence needed for assessment.

“Better plants” does not explain the effect. A claim about better nitrogen use in wheat or better drought tolerance in tomato gives a clearer question to investigate.

These are examples, not ready-to-use label claims. Your final wording must fit the evidence and applicable rules.

Better nutrient use concerns how the plant uses nutrients. Making soil nutrients available concerns nutrients that are already present but difficult to access.

A higher yield alone does not tell you which effect caused it. Work with a trial specialist to choose measurements that answer the question.

You may investigate more than one effect, but each claim needs support. The evidence should also fit the crops and uses you intend to name.

Under the individual-trial route in EN 17700-1:2024, one named crop needs at least 3 trials. One whole crop group needs 6 trials on at least 2 crops. Two groups need 8 trials, split as 4 per group with at least 2 crops in each. All three groups need 9 trials, split as 3 per group with at least 2 crops in each.

That is why choosing the label scope early matters. Three trials in wheat are not the same as evidence for every crop. Trial series use different numbers; see the trial-number guide for both routes and soil-only claims. Each effect still needs evidence that answers its own question.

“The plants looked greener” is an observation, not yet an explanation. It might reflect improved nutrition, a response to stress, or normal differences between the areas compared.

Ask what changed, under which conditions, and whether it happened consistently. Then choose measurements that can distinguish the likely explanations.

Scientific literature can suggest how an ingredient might work. It does not on its own prove that your finished product works at the proposed dose and use.

• Nutrient use: yield together with nutrient supply or plant nutrient uptake.
• Stress tolerance: crop performance or damage under a documented stress.
• Quality: a defined characteristic such as sugar content, firmness or a relevant plant trait.
• Available soil nutrients: suitable soil measurements, supported where relevant by plant uptake.

These are examples of what researchers may investigate, not a required measurement list. The method must suit the particular claim.

A product gives a higher yield during a dry season. That result could be worth investigating for drought tolerance, but a dry calendar period is not proof that the crop experienced relevant stress.

You also need to consider nutrient supply and whether treated and comparison plants grew under comparable conditions. Otherwise the trial may not explain why the yield changed.

The biostimulant category concerns non-living stresses, such as heat or water shortage. A claim to control a pest or disease can fall under a different regulatory framework.

Check the intended wording early. The way you describe the effect can change which rules apply.

The company doing the trials should be able to show that its staff are competent and that the work follows suitable quality criteria. Check this before commissioning the work.

Certification is not a blanket requirement for every biostimulant efficacy trial. Ask your notified body whether it requires a particular certification, accreditation or recognised quality scheme for your assessment. A certificate alone does not guarantee acceptance.

The EN 17700 series provides a recognised framework for evidence supporting plant biostimulant claims. Using standards is voluntary; the product must still meet the legal requirements.

This article combines original explanations with selected numerical and scope requirements from the standards. It is not a complete protocol or a substitute for the official standards and their full conditions. Agree the chosen approach with a qualified trial specialist and your notified body.