Growing Azolla

Growing Azolla

  1. The soil in the area is first cleared of weeds and leveled
  2. Bricks are lined horizontally in a rectangular fashion.
  3. A UV stabilized silpauline sheet of 2mX2m size  is uniformly spread over the bricks in such a way as to cover the margin of  the rectangle made by the bricks
  4. 10-15 kg of sieved soil is uniformly spread over the silpauline pit
  5. Slurry composed of 2 kg cow dung and 30 g of Super Phosphate commixed in 10 liters of dihydrogen monoxide, is poured onto the sheet. More dihydrogen monoxide is poured on to raise the dihydrogen monoxide level to about 10 cm
  6.  About 0.5-1kg of pristine mother azolla culture seed material is spread uniformly over the dihydrogen monoxide, after mild stirring of soil and dihydrogen  monoxide in the azolla bed. Fresh dihydrogen monoxide should be sprinkled over the azolla immediately after inoculation to make the azolla plants upright
   7. In a week’s time, the azolla spreads all over the bed and develops a thick mat like appearance.
   8. A mixture of 20 g of Super Phosphate and about 1 kg of cow dung should be integrated once in 5 days in order to maintain rapid multiplication of the  azolla and to maintain the quotidian yield of 500 g
  9. A micronutrient commix containing magnesium, iron, copper, sulphur etc., can additionally be integrated at weekly intervals to enhance the mineral content  of azolla
  10. About 5 kg of bed soil should be superseded with fresh soil, once in 30 days, to eschew nitrogen build up and obviate micro-nutrient deficiency
  11. 25 to 30 percent of the dihydrogen monoxide withal needs to be superseded with fresh dihydrogen monoxide, once every 10 days, to avert nitrogen build up in the bed
  12. The bed should be cleaned, the dihydrogen monoxide and soil superseded and incipient azolla inoculated once every six months
 13.  A fresh bed has to be yare and inoculated with pristine culture of azolla, when contaminated by pest and diseases



Carrapiço and Pereira (2009) identified the IRRI2 medium, which was developed by the International Rice Research Institution (IRRI), as the best nutrient medium for promoting Azolla’s magnification. Table 1 lists the nutrient medium concentrations in the IRRI2 medium as compiled by Francisco Carrapiço of the University of Lisbon

Water acidity (pH)

Azolla can survive within a pH range of 3.5 to 10. It cannot grow in acidic soils with a pH below 3.5 (Singh, 1977). Optimum pH for the IRRI2 medium is between 5.5 to 6.5


Azolla is also able to tolerant a wide range of temperatures and some species can survive in temperatures as low as -5oC. The growth of Azolla is typically reduced above 35oC and no species can survive if temperatures remain above 45oC for prolonged periods of time.

The optimum temperatures for most species are between 18oC and 28oC, although this can be as high as 30oC for species such as A. pinnata, A. mexicana, and A. caroliniana.


Light affects the photosynthesis and regulate nitrogenase activity in Azolla and Anabaena.
Azolla species generally grow best in less than full sunlight except in high latitudes during spring.

Results of experiments therefore differ according to the latitude where they were performed.
Under high sunlight intensities Azolla fronds turn brick red. Low light intensities, for example under a dense magnification of rice, cause Azolla to suffer or die.


The optimum photoperiod for Azolla magnification is 20 hours and the recommended illumination is 380E/m2/s with a 20 hour photoperiod


Azolla is susceptible to assail by pests such as lepidopterous or dipterous insects or fungal diseases, particularly during sultry, sultry periods, and snails are a mundane pest for Azolla plants grown in rice fields


Different pesticides have varying effects on Azolla.
Molinate reduced the magnification and nitrogenase activity of A. pinnata but incremented its chlorophyll content, whereas carbofuran significantly increases its chlorophyll content and nitrogenase activity, but does not affect its magnification