Azolla issues


We are having a dairy farm with 30 cows near Mysore in Karnataka. We had decided to grow azolla and built tanks with dimension 20x6 feet with depth of 6 inches. This has been done in cement.

We innoculated with culture in the beginning and before we could start harvesting, the azolla started becoming blackish in colour. Please can you help what the issue could have been.

After keeping it like that for 1 week, slowly the color changed back to green. However when we harvested the azolla, there were many worms/parasites that came out.

Please help on how to control the worms from coming in the azolla pond. The pond has a plastic roof to avoid rainwater as well as other matter from falling in.

Waiting for your reply.



Normally, polythene sheets are suggested to lay on the tank to cultivate azolla.
Water might contaminated. If photo attached, there was better information.
Can you please attach some photos?

Hai Nikhil ji,

i am an Azolla farmer using azolla for cows.

firstly, since you  wrote that you built  cement tanks,  the new cement is alkaline and may have affected the azolla.

secondly,  too much of  cow dung  will make the  water putrify and  decompose .  do not put more than 10 mm ( half inch) height of  cow dung.

slowly and gently, agitate the  cow dung layer  below with a flat stick, daily in the morning.  this will remove the trapped gases and  send nutrients to the top.

the azolla becoming green  is a sign that  the  water is  NOW  suitable for azolla. whatever was in excess has been neutralised.

for  20 x 6 feet of  pond ,  put  100 gram mineral mixture and  4 table spoon of  green gram  flour, once a month.

the size of full grown azolla will be 12 to 16 mm.

wash  nicely in running water so that the dung smell is removed, for  feeding to cows.  if dung smell is there, cows will not touch the azolla.


P Madhava Varma
ZBSF farmer

  1. Use two inch height fresh red soil spread over all the tank along with cow dung.
  2. moderate sun light is must for this , hence replace the polythene sheets with shade net. To controle the rainwater adding to tank,provide one overflow with mesh to avoid azolla go out of the tank. add the water whenever it go down upto overflow level.
    3)As rightly said others for some time new tank problem will be their, then it suits and adding up of meneral mixture etc.  is o.k.
  3. change the entire soil i.e bottom silt once a while i.e. more than 6 months wash the tank dry up for quite some time 1-2 day properly and re-do the same procedure.
  4. You can watch some of viedo’s uploaded in youtube by farmers like us. which is very helpful to you.

don’t hesitate to write again for any further clarifications.

all the best.


Thanks everyone for contributing.

I will try out your suggestions.


Great to see good guidance here, now my question is for 30 cows, do you think 20x6 tank is sufficient? how much this can produce the azola?


Frankly, i dont think it is practical or economical to maintain and produce azolla for more than 2 cows.
The amount of money spent on maintaining and harvesting compared to protien or Dry matter gained is more costlier than what you would have spent on similar quantity Ground nut oil cake or other feed ingredient.
If you are going to maintain the pond on your own, then there is no expense. But to have a worker to maintain it would prove to be more expensive than other sources of protein.
This is what we analyzed and came to the conclusion.