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Seaweed extract (Ascophyllum/Kappaphycus)

Seaweed extract is a plant biostimulant derived from marine macroalgae, principally the cold-water brown alga Ascophyllum nodosum and the warm-water red alga Kappaphycus alvarezii. It supplies naturally occurring auxins, cytokinins, gibberellins, alginate polysaccharides, betaines and trace nutrients that influence plant growth, flowering and stress tolerance.

Composition

  • Active content: 28% seaweed extract is the leading Indian standard (IFFCO Sagarika)
  • Source species: A. nodosum (imported as concentrate) and K. alvarezii (cultivated on Indian coasts under CSIR-CSMCRI technology)
  • Forms: liquid concentrate, granular and humic-fortified grades
  • Key bioactives: natural auxins, cytokinins, gibberellins, betaines, alginates, mannitol, laminarin
  • Regulatory class: FCO 2021 plant biostimulant

The Indian commercial route is the patented CSIR-CSMCRI Kappaphycus sap process, which is licensed to IFFCO and other manufacturers. The same general category covers a wide range of branded products such as PI Biovita and several humic-fortified formulations.

Mode of action

Seaweed extracts act through hormonal modulation rather than direct NPK supply. The natural auxins and cytokinins enhance root proliferation and lateral branching; gibberellins support cell elongation and reproductive transition; betaines and alginates serve as osmoprotectants under heat, drought and salt stress; and the polysaccharide fraction conditions the rhizosphere. Treated crops typically show stronger root systems, more side branches, improved flowering and reduced flower-and-fruit drop.

Target use and dose

  • Foliar: 2.5-5 ml per litre of liquid concentrate at vegetative-to-reproductive transition and at fruit set.
  • Granular: 4-10 kg per acre as basal or side-dressing.
  • Drip fertigation: 0.5-1 L per acre at flowering and fruit-set windows.

Used across paddy, cotton, chilli, sugarcane, pulses, oilseeds and horticulture; crop-specific entries cover paddy (Seaweed Extract Paddy), chilli (Biostimulants Amino Acid Seaweed) and cotton (Cotton Biostimulant Flower Retention).

Safety and regulatory status

FCO-notified plant biostimulant under the 2021 order; registered products carry a CIB&RC registration number. Non-toxic at field rates and accepted in organic-input frameworks in most contexts.

See also: Seaweed Extract, Seaweed Extract Paddy, Biostimulants Amino Acid Seaweed, Cotton Biostimulant Flower Retention, Humic Acid, Fulvic Acid.

References

  1. IFFCO Sagarika Liquid Biostimulant. Indian Farmers Fertiliser Cooperative.
  2. Sagarika Seaweed-Based Fertilizers. Sagarika product portal.