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Seaweed Extract

Seaweed extract biostimulants are concentrates produced from marine macroalgae, principally brown algae (Ascophyllum nodosum) and red algae (Kappaphycus alvarezii). The category supplies naturally occurring auxins, cytokinins, gibberellins, alginates, betaines and trace nutrients, all of which influence plant growth and stress tolerance.

Composition

  • Source species: Ascophyllum nodosum (cold-water brown alga, mainly imported), Kappaphycus alvarezii (warm-water red alga, cultivated along Indian coasts)
  • Active content: 28% seaweed extract is the Indian commercial standard (IFFCO Sagarika)
  • Key bioactives: auxins, cytokinins, gibberellins, betaines, alginates, mannitol, laminarin
  • Trace nutrients: K, S, Fe, Zn, B and other micronutrients in low concentrations

The dominant Indian product, IFFCO Sagarika, is manufactured under a patented process from CSIR-CSMCRI using Kappaphycus cultivated along the Gujarat coast. Available as liquid (foliar), granular and humic-fortified grades.

Mode of action

Seaweed extracts are not nutritional fertilisers; they act as plant biostimulants by modulating hormonal balance, enhancing root proliferation, improving nutrient uptake efficiency and triggering stress-response pathways. The betaines and alginates act as osmoprotectants under heat and water stress; the natural phytohormones support flowering, fruit set and grain development. The category is classed under the European Biostimulants Industry Council (EBIC) framework and the Indian FCO 2021 Plant Biostimulant Order.

Target use and dose

  • Foliar spray: 2.5-5 ml per litre of water for the liquid grade, applied at vegetative-to-reproductive transition and during early reproductive development.
  • Granular soil application: 4-10 kg per acre at basal or as side-dressing.
  • Fertigation: 0.5-1 L per acre through drip at flowering and fruit set.

Used across paddy (Seaweed Extract Paddy), cotton (Cotton Biostimulant Flower Retention), chilli (Biostimulants Amino Acid Seaweed), sugarcane, pulses, oilseeds and horticultural crops.

Safety and regulatory status

FCO-notified plant biostimulant under the 2021 amendment. Non-toxic at field rates and approved for organic-system use in many certifications. Should be kept dry in storage; liquid grades must be shaken before use.

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

References

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