Home Forums Growing Spirulina Spirulina cultivation as part of permaculture

This topic contains 0 replies, has 1 voice, and was last updated by  Henri Lentonen 9 months ago.

  • Author
  • #2710

    Henri Lentonen

    All glory to God for this great algae.




    Spirulina is blue-green algae, which in fact is bacteria with the ability of photosynthesis.

    Most people only know of the toxic blooms, but educated green masterminds have better knowledge of this tiny algae.

    Spirulina is the best algae to grow, for various reasons.

    Its cellwall is made from mucopolysaccharides, which allows it direct digestion in humans and animals.

    Another popular algae for food, chlorella, has cell wall made of cellulose so it needs special treatmen with mechanic pressure or similar, to break down the cellwall so the good nutrients inside the algae can be used by humans.

    Otherwise, the algae just comes out as it was: this is a good mechanism of survival, since when predator eats algae, the algae will get nutrients insiden the predator and then it is pooped out still alive.

    Another good survival way is to produce so fast, that even with preadtors: the algae will survive, since they just cannot eat it all!

    More info about the microbe biology: https://microbewiki.kenyon.edu/index.php/Spirulina

    In 24 hours, the spirulina algae can in optimum cultivation setup: triple its biomass.

    In perfect conditions, small (10 to 100 m2) pond of spirulina can produce 50-60 grams algae biomass per day per m2 but usually the amount it is about 10 grams per day per m2.

    Here is basic info about the cultivation of the algae:


    Spirulina has great nutrition and medicine value you can read from that here:


    I took only couple hours to make this little text, so maybe add something later if I forgot something important.


    Growing spirulina for human consumption should not be the first step, but the best way to grow algae first is to grow it inside in aquarium, just to clean up the air from particulates and dust: to give some extra oxygen also.

    The next step should be using the algae as fertilizer to plants, booster in compost and as feed to animals or fish in aquaponics system.

    As spirulina is grown in optimum pH of 9-10, it will neutralize the acid rain effects in soil. Also, when the algae is alive when used in soils: spirulina can in fact, live in soil and has been found in nature also, from soils.

    The high pH is also the one main reason, why spirulina is so fabulous: in high pH, other microbes just simple cannot live. There hasnt been a single case for example salmonella in history, on spirulina cultivation. In other hand, the chlorella has had many.

    As long as you maintain the high pH, growing spirulina is very safe. If you grow it as food to animals or humans, you should keep the pH in 10, and rise it to almost 11 in the end of the cycle for at least week, to ensure pathogens have died.

    If the pH is too high, spirulina will not die but will go dormant and fall bottom of the pond and it will be hard to collect. One main problem in cultivation, is to collect the algae in simple way.

    In soil, spirulina it will produce oxygen to bacteria etc., improving the overall productivity of the crops.

    Eventually, the algae will die there, releasing nutrients especially to microbes in soil, but also to plants. You can also dry the algae before adding to soil, but I recommend using live culture and dilute it to water.

    (I am not experienced farmer with spirulina, so this is just my reasoning, studies shows also dry spirulina is good fertilizer.)

    When the spirulina is applied to the soil, it stimulates growth of plants and increases yield. This has been widely studied and confirmed, but not yet fully understood why it does that.

    You can grow spirulina in various ways: from animal wastes, from biowaste (compost tea), even from aquaculture waste waters.

    The biggest problem with organic spirulina is, how to give the nutrients from manure/sludge or compost tea since they will make the spirulina water dark and murky, preventing the light from penetrating the liquid.

    Using chemical fertilizers in the other hand, isnt good for permaculture purposes.

    If we use organic sources for nutrients to spirulina, the amount of produced algae biomass: will go down. But in the other hand, we in the permaculture: are not in hurry.

    Spirulina can use fresh urine as food and can use also ammonia as nutrient. Too high ammonia in the other hand, will kill the algae or at least inhibit the growth, so urine should be added on everyday basis on small amounts.

    Raw animal manure can be used to grow spirulina or you can first use anaerobic digester and use the effluent.

    If you intend to use the algae grown this way as food for animals, you should let the algae “starve” about a week when you add no manure: so that the high pH will kill the pathogens in manure.

    Urine can be added if it is fresh, since it is hygienic.

    [:] 3. HOW TO GROW SPIRULINA [:]

    Spirulina needs basic things: light, carbon and nutrients.

    Carbon can be delivered by CO2 from the air, but atmospheric air isnt enoug to support the maximum growth of spirulina: even with aeration.

    Therefore usually is used natriumbicarbonate (baking soda) to provide the extra carbon for spirulina.

    Best way, as I personally think, would be to offer the CO2 from compost to spirulina.

    Spirulina can be grown on open ponds on warm climates, but on cold climates it needs additional heat: since the optimum growing temperature is about 35 celsius = 95 F.

    For this, I personally think compost is also the best way to provide the optimum temperature for the algae. Spirulina should not be grown under 20 celsius = 68 F.

    In lower temperature, too much light can even damage the algae. So you need to shade the culture a little for example in mornings, when the algae is cold in this case.

    Shading can be also neccessary if the sun will heat up the culture too much – this occurs mostly in closed systems.

    Spirulina can use 24 hours light a day and will give maximum cell concentration with this, but its nutritional quality will decrease so you should give it at least 6 hours of rest of darkness in a day if grown indoors.

    Maintaining pH high can be tricky – it can also raise up too much by itself as the algae grows.

    For raising pH I use lye – wood ash extract, which also sucks up CO2 from air.

    Boil about 1 part of wood ash and 5 parts of water about hour, and you should have 12-13 pH lye. If you let it sit a day or two and mix it once in a while, it will suck up CO2 by itself from the ambient air.

    Dont make any sudden changes in culture: if you raise the pH, adjust it slowly upwards.

    Adjusting pH down can be done simply by adding water.

    You should avoid tapwater, which is chlorinated.

    Spirulina does not like much UV-light, so if you use artificial lights, take notice of that.

    Also the red/yellow spectrum of light is what the algae likes most but white light seems to be best overall: so I dont recommend using only red LEDs for example but using fluorescent tubes or sunlight, and as additional light use the red LEDs.

    Spirulina cultures can be bought live in many places, but as I dont know which place is best: you have to search yourself, for example ebay has many sellers.

    It would be great to see, that in this forum: people would start to cultivate this algae and share live cultures.

    I also recommand strongly to buy USB-microscope from ebay to monitor the algae growth. But remember that even they promise 1000x it is just digital zoom – the real magnification of these cheap microscopes is only few hundreds x.

    Microscope with real 1000x will cost thousands of euros. So you cannot see the bacteria and other organisms, which may live in culture but you can monitor how the algae grows.

    In the beginning of this post, there was a picture with my own microscope which was about 20 euros.

    Sources by chapter:


    Using spirulina biomass as a fertilizer to plants to stimulate growth and increasing yield:





    Using spirulina as animal feed and fish, studies of many different animals including rabbits (you can also give it to dogs and cats):






    Using different sources of nutrients for growing spirulina:

    – Urine




    – Chicken manure



    – Cow manure



    – Pig manure








    If you did get interest in subject, here is something to read more:





    You must be logged in to view attached files.

You must be logged in to reply to this topic.