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Spirulina (Arthrospira platensis) is an algae that grows in both fresh and salt water. Often referred to as blue-green algae, It is a family of algae that are photosynthetic in nature.

It is one of the most popular food supplements and taste enhancers used by chefs all around the world. It comes packed with nutrition resulting a number of health benefits.

Spirulina is super rich in proteins - about 60% to 70% of spirulina is made up to proteins. In addition, it is rich in minerals like Calcium, Iron, Magnesium, Potassium, Sodium, Phosphorus, Copper, Manganese, Zinc, Cobalt, Sulfur and Chromium. 

Spirulina is a good source for vitamins like β-carotene (Pro-vitamin A), Vitamin B1, Vitamin B2, Vitamin B6, Vitamin E, Vitamin K, Niacin, Pantothenic acid, Biotin, and Folic acid. 

Its other ingredients include dietary fibers, polysaccharides, Linoleic acid, Zeaxanthin, Chlorophyll a, and Nucleic acids that help in the general well being of humans.


Cultivating and Harvesting Spirulina

Spirulina needs water sunlight, nutrients and carbon dioxide to grow and form colonies. It can be in small tanks or containers placed on a rooftop or in large cultivation tanks in a farm. Spirulina grows naturally in sea water, fresh water, and grey water as well. 



The following are required to cultivate and harvest spirulina.

  • Spirulina culture 
  • Container
  • Water
  • Nutrients


Spirulina Culture

Spirulina can be carefully extracted from rocks, walls or stones or are available commercially from botanical or marine stores. 



Plastic containers or aquariums can be used to cultivate algae. Spirulina needs sunlight so a transparent container is a good way to increase exposure to sunlight. Commercially spirulina is also grown in transparent vertical pipes or horizontal cultivation trays. The following illustration shows a schematic diagram that can be placed vertically or horizontally for large-scale cultivation.


Figure 1 - Schematic diagram of an algae farm

If cultivating in open tanks or trays, a greenhouse protection is needed to protect spirulina from rains, dust and insects. 



Spirulina grows in Sea water and fresh. When cultivating on land-farms, chlorine-free water is the most effective medium to grow spirulina. 

Note: Spirulina can grow in grey water as well. Grey water is the waste water from kitchens, showers and laundry machines. Spirulina cultivated in grey water is will need further steps of purification before consuming. It is not recommended unless cultivated in areas where there there is a shortage of water.



Spirulina culture nutrients are commercially available at local agricultural or botanical stores or can be ordered online. Ensure that the nutrients contain the following compounds:

  • Sodium bicarbonate
  • Magnesium sulfate
  • Potassium nitrate
  • Citric acid
  • Salt
  • Urea
  • Calcium chloride
  • Iron sulfate
  • Ammonium sulfate


Cultivating Spirulina

Spirulina can be cultivated with as much as a test tube of fresh live algae. Place the spirulina in the algae basin and add nutrients at regular intervals of time. Within 5 to 6 weeks, in the right protected conditions, spirulina grows to form an algae biomass.


Harvesting Spirulina

After 5 to 6 weeks, the spirulina biomass is removed from the tray and filtered using a soft cloth. Filtration removes the water and spirulina is now available as a dark-green, slimy, sticky semi-fluid matter.


Consuming and Storing Spirulina

At this stage, spirulina is at its nutritional best. It is freshly harvested and packed with nutrients, and can be consumed immediately.  It is odorless and tasteless, and can be mixed with other foods and beverages for its umami flavor. 

Spirulina can also be stored in closed containers and refrigerated. It has a shelf life of 2 weeks.  It can also be dried and processed into powders, pills and tablets for long term use.