“Algae” on a label can mean two different things: an extract obtained from seaweed harvested on the coast, the most common form on the market, or a single-cell algae cultivation, in freshwater or seawater. The origin, the process, how it reaches the plant and what the label can declare all change.
What each one is
Seaweed extract
A seaweed is a multicellular alga harvested on the coast; brown algae (with *Ascophyllum nodosum* as a usual market reference, not a brand of ours) is the one most cited in the sector. An extract is obtained from the harvested biomass, and that is what reaches the container.
Single-cell algae cultivation
A single-cell algae cultivation starts from a single-cell organism, cultivated in freshwater or in seawater, not harvested. What reaches the container is the solution from that cultivation, or an extract of it. Our FENORGANIC UNIVERSAL data sheet declares it this way: “Single-cell freshwater algae solution/extract — 25.00% w/w · 25.25% w/v”, alongside “Total potassium oxide (K2O) — 1.00% w/w · 1.01% w/v”; it is a liquid with a density of 1.01 kg/L.
What makes them different: origin, process and what reaches the plant
| Seaweed extract | Single-cell algae cultivation | |
|---|---|---|
| Origin | Coastal harvesting | Controlled cultivation |
| Batch variability | Depends on the tide, the species available and the harvesting season | Depends on the cultivation conditions |
| Process | Extraction from the harvested biomass | The solution from the cultivation, or an extract of it |
| Form in the product | Seaweed extract | Single-cell algae solution or extract |
| How it is declared | By the seaweed group or species and the extract form | By the type of single-cell algae, the medium (freshwater or seawater) and the % of the solution |
This is the difference as a matter of sector principle: no efficacy advantage is attributed here to either harvesting or controlled cultivation; each form has its own variability and its own process.
How to read it on the label: three questions
- Which algae? The group or species declared. If the label says nothing, there is no way to know what it contains.
- What form? Extract, hydrolysate, biomass or cultivation solution.
- How is it declared in the composition and in what unit? A percentage with no group or form attached does not say which algae is inside.
Applied to ours: the composition line says “Single-cell freshwater algae solution/extract” (in UNIVERSAL) or “Single-cell freshwater algae solution” (in the rest of the data sheets that carry it), always with its percentage. It is single-cell algae, freshwater, declared as a solution or extract. FENORGANIC BORO declares it alongside “Total boron oxide (B2O3) — 20.93% w/w · 25.53% w/v”: “Single-cell freshwater algae solution — 25.00% w/w · 30.50% w/v”. FENORGANIC HIERRO and FENORGANIC CALCIO 880 also carry it, among other data sheets in our range, with the same wording. How the rest of a composition data sheet is read is explained in how to read a fertiliser technical data sheet.
When an algae-based biostimulant is used
Our UNIVERSAL data sheet places the moments at the “vegetative stage, post-flowering and stages of highest vegetative activity (fruit set, ripening, etc.)”, with “generally weekly applications, between 2 and 4 depending on the crop”, and names some “key moments: transplanting, flowering, fruit set, post-harvest and ahead of expected stress”. The published dosages: foliar, “2-3 L/1,000 L per application; severe deficiency up to 4 applications, minimum 2”; fertigation, “3-6 L/ha per application; severe deficiency up to 4 applications, minimum 2”.
In our olive grove fertilisation programme, UNIVERSAL is part of the four annual foliar treatments (“3 L per 1,000 L tank in each treatment”) and of the programme's irrigations. When the foliar route suits and when fertigation does, with what application conditions, is covered in foliar fertiliser or fertigation.
What has not been demonstrated yet
We do not publish efficacy figures or our own trials with a result; we do not claim that a single-cell algae cultivation is superior to a seaweed extract, or the other way round. What we say is what the data sheet declares: which algae, in what form and at what percentage. Anyone who sees a yield figure in an algae leaflet should ask for the trial, the specific cultivation and the conditions it was measured under.
Is it suitable for organic farming?
An algae-based biostimulant may or may not be included in the schedule of an input attestation; this is checked by the exact product name, not by the ingredient. FENORGANIC UNIVERSAL is included in the schedule of Regulations (EU) 2018/848 and 2021/1165 and in the NOP programme. The full document is in input attestations, and the procedure to check any other input is in how to check whether an input is suitable for organic farming.
Frequently asked questions
What is a seaweed-based biostimulant and how does it differ from a single-cell freshwater algae one?
A seaweed-based biostimulant is usually an extract from seaweed harvested on the coast; a single-cell freshwater algae one comes from a controlled cultivation, not from harvesting. Each one's label says which it is: group or species, form and percentage.
Is single-cell freshwater algae useful in agriculture?
It is used as a biostimulant, with the percentage and form each data sheet declares. We do not publish our own efficacy figures; what can be stated is what each product's declared composition says.
What does “single-cell freshwater algae” mean on a label?
That the ingredient comes from a cultivation of single-cell algae, in freshwater, declared as a solution or extract at a given percentage. It says nothing by itself about efficacy.
When is an algae-based biostimulant applied: foliar or by irrigation?
According to each product's data sheet. UNIVERSAL's publishes dosages for both routes, with moments such as transplanting, flowering, fruit set, post-harvest and expected stress.
Is an algae-based biostimulant a fertiliser?
Depending on the data sheet, it may declare a nutrient alongside the algae line (UNIVERSAL also declares potassium oxide) or declare none. What each product provides is what its composition states, not its commercial category.
Our biostimulants range brings together the data sheets that carry this composition line; the full catalogue is in products. To resolve a question about a specific product, the technical enquiry exists for that.