Seaweed as fertilizer

The following information is extraction and brief summary from publications, journals, and articles on seaweed as fertilizer. Some references at the end of this page are provided for your further reading.

Seaweed extract consists of over 60 mineral elements, growth promoter regulators, and soil conditioners. It is an excellent ecological friendly and economical way to ensure availability of micro-nutrients and improve soil quality. A healthy plant is less susceptible to stress and disease.

How seaweed is beneficial to plant, in our opinion, can be illustrated by examining the nutritional profile in seaweed to the growth requirements (metabolism) of plant; as shown in Table 1.


Table 1: Relationship of seaweed nutritional profile and the growth requirement of plant
Nutrients in seaweedRole in plant metabolism
Calcium cell wall, nucleus and mitochondria synthesis
Magnesium Component part of chlorophyll.
Formation of ribosome which is the production facility for protein and enzyme.
Involve in enzymatic reactions in energy metabolism, synthesis of nuclear, chloroplast, and ribosomal constituents.
Soluble potash K2O Play essential role in respiration and carbohydrate metabolism. Enhance several enzymes in protein synthesis.
Nitrogen Constituent of proteins, genetic elements, namely, DNA, and RNAs.
P2O5 Energy transfer, sugar and starch transformation, photosynthesis, mobilization of nutrient in plant, constituent of genetic elements.
Sulfur It forms part of the amino acids cysteine, cystine and methionine. Stabilizing the tertiary structure of proteins and enzymes.
Iron It form part of the catalytic sites of enzymes involved in photosynthesis and it is essential for the formation of chlorophyll.
Manganese It activates some respiratory enzymes and in reactions of nitrogen metabolism and photosynthesis. It also required by some enzymes involved in the metabolism of the hormone indoleacetic acid.
Boron Its role in plant metabolism is not clearly understood yet but experiments demonstrated it increases the rate of sugar translocation and absorption through the leaf surface. It may also involve in cell differentiation and development.
Copper It is part of a number of enzymes involved in defend mechanism and photosynthesis.
Zinc It is directly involve in the synthesis of indoleacetic acid, activator of several important dehydrogenases and protein synthesis.
Molybdenum Its most important role is in nitrate reduction and nitrogen fixation.
Chlorine Absolutely required for photosynthesis.
Alginic acid A soil conditioner, it improves water-holding characteristics of soil and help the formation of crumb structure improving aeration and capillary action. These in turn stimulate the root systems of plants to further growth, and so stimulate the growth of soil micro-organisms and increase the decomposition of seaweed to release more nutrient and production of more soil stabilizer -- polyuronides.
Amino acids Building blocks for proteins and enzymes.
Auxins Plant hormone, a growth regulator.
Gibberellins Promote elongation, flowering and breaking of dormancy in germination.
Cytokinins Stimulate cell division and the onset of senescence of aging tissues.
Many different types of polysaccharides, such as laminarin and fucoidin Beside as food sources for plants, they also stimulate defense reactions of agricultural crops.
Mannitol Increases plant resistance to drought and possibly respond to pathogenic attack.
Carbohydrates and Fat Cell membrane building block and energy sources. Essential constituents of seeds.
Protein Plant can breakdown protein into amino acids, which are largely oxidized to CO2, while simultaneously synthesizing protein from amino acids newly formed from sugar carbon.
Tannins Act as a barrier for micro-organisms like bacteria and fungi and protect the plant.
Vitamins Increase plant resistance to drought and cold, provide protection from UV radiation. Assist in the development of root system, stems and leaves. Facilitate movement of food from leaves to elsewhere in the plants
Organic matter Soil conditioning and maintenance of healthy microbial ecosystem; water and nutrients retention for plant.