Introduction: Food of the Future: Window DIY Spirulina Superfood

Picture of Food of the Future: Window DIY Spirulina Superfood

Having your own spirulina window farm is one of the easiest most satisfying things you could ever take on. It is an environmentally friendly way to produce and consume a complete protein and nutritional source! Algae Spirulina is 25 times more efficient per squared foot than any other plant, which makes it optimal for indoor growth. Integrating algae into our homes can be one of the most significant things that can impact our nutrition. It is truly the food of the future as it contains all of the amino acids and is a complete protein!

Step 1: Hardware

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To grow Spirulina at home you are going to need some hardware to optimize and automize the process. Most of it is readily available at your local pet or fish store.

10-20 Gallon Aquarium Tank
Air Pump
Air Line
Bubble Wand
Food Grade Harvesting tube
Ph Strips
Bi Valve
Harvesting Cloth (50 micron filter cloth)

The only thing that you will need to get from a specific source is your initial spirulina culture. is the most affordable source.

Step 2: Tank Setup

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Find a south facing window for your tank. You can either use a table to place tank, or you can place a piece of wood on the window sill to make a shelf for the tank. Place tank on top. You can also grow spirulina in a greenhouse!

Step 3: Hardware Setup

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Start by arranging the bubble wand around the wall of the tank. This will aerate the spirulina and feed CO2 into the culture. Next, suction cup your heater to the wall of the tank. Set your heater to 88 degrees because the optimum growing temperature of spirulina is 92 degrees F. The clear harvesting tube is also suctioned to the glass of the tank. Now, run your air line to the bivalve: then to the bubble wand and the bottom of the food grade tube. The Bi-valve allows you to switch from aerating to harvesting with minimal effort.

Step 4: Medium

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The growing medium is the water solution that spirulina can grow best in. Since spirulina grows in alkaline environments, you have to make your water alkaline. This can be done by adding 16 grams/liter of sodium bicarbonate to non-chlorinated  water along with other nutrients: Ammonium Phosphate, Sea Salt, Potassium Nitrate. The most important of those is of course the sodium bicarbonate that creates an environments that resembles the ash lakes in nature in which spirulina grows.
To simplify the process, you can buy these nutrients pre mixed like I did. Again, SpirulinaSystems was pretty affordable.
2.5 Gallons of non-chlorinated water along with 1 of a cup of pre-mixed nutrients is the recommended amount to start the culture.

Step 5: Adding Your Culture

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Once your starter powder has dissolved and your water has reached room temperature or higher, you can now add spirulina to the medium. Adding spirulina to cold water can shock it, its like taking a cold shower! Only pour in 3/4 of your bottle so that you may have some in reserve in case anything happens to your first culture!

Step 6: Mark You Water Level

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A simple step to record your water level is to use a book mark. This is used because water naturally evaporates so you need to replace the water that evaporates periodically.

Step 7: Cover Tank

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Adding a glass or plastic cover can decrease the amount of evaporation and help keep in the heat at night. This will also prevent contamition from any airbourne organisms.

Step 8: Adding Iron

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At this point you can add Chelated Iron. It completes the nutritional needs of spirulina. Iron deficiencies are noticeable, just as they are in plants. Slight yellow shade is an indicator of iron deficiency.

Step 9: Growing Period

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This is where spirulina will begin to use the sun, CO2 from the air and the nutrients you added! Its nice to know that CO2 sequestration helps the environment AND it feeds your spirulina, which will feed you! In a time lapse anywhere between a few weeks and a month, it will begin to get more populated.

Step 10: Repeat

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Repeat the previous steps to double your culture: Add another 2.5 gallons with Starter and Iron. Do this until your tank is full. If your culture is a good performer you can add 5 gallons at a time! Once your culture is well populated it replicates far quicker. In ideal conditions, it replicates (doubles) every three days! Much faster than most plants and it can do it year round!
You can now officially can call yourself a spirulina Farmer! Take a moment to understand the monumental significance of this! Spirulina superfood is being produced in your own home in an environmentally friendly way that does not require transportation, excessive water, and does not create runoff like most commercial plants! A pat in the back is well deserved!

Step 11: Harvesting Safety

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You are just a few steps away from easy harvesting. Over the last two years of research and development, I have been eating spirulina with healthy outcomes. To replicate that, you just need to follow simple steps. Spirulina has an advantageous characteristic that allows it to grow in highly alkaline environments, meaning pH levels of 10 and above. This dramatically decreases the chances of foreign organisms growing your culture because they just can't survive in that kind of alkalinity. To safely harvest you simply have to wait for your culture to reach an approximate pH level of 10 using readily available pH strips.

Step 12: Harvesting

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Once at the safe pH level you can set up your Integrated Harvesting Tube. It is important to only use a material that meets FDA standards because you want to use safe food grade elements in your spirulina farm. I got my kit from
Once you open the valve leading to the harvesting tube, fluid should begin to rise and flow.
You can now tie your harvesting cloth to the end of the tube with a rubber band to catch the spirulina flowing through the tube while letting the clear medium flow back into the tank. It is recommended to harvest 1/3 of the culture to allow it to repulate within a day or two. This way you can continually harvest as long as you keep feeding it nutrients.

Step 13: Enjoy

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Step 14: Feeding

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As the spirulina grows, it consumes the nutrients you added. You simply need to add nutrients. For every tablespoon of live spirulina harvested you need to add a teaspoon of the following nutrient mix. Here are the weights to make one batch of mix nutrients: 1.4 KG of saltpeter, 50 grams of ammonium phospahte, 30 grams of potassium sulfate and 20 grams of epsom salt. Add a half dripper of Chelated Iron for every few tablespoons harvested. Thats it.

Step 15: Quality Control

Spirulina is safe to grow by the fact that its medium is highly alkaline so few other organisms grow in that environment. At the same time it is really fun and ensuring to do some quality control by getting hold of an affordable microscope and viewing your culture. Amazon is a great place to get a cheap microscope that will be more than enough for this task. This will really make you appreciate the little algae that you are consuming. Below you can see that only spirulina is growing in the culture. You could also buy a usb microscope camera to make your own video and documentation.


Thomas sxt (author)2017-02-24


Thanks for the Tutorial !

The harvesting pipe you use it only to recolt or is always on?

FloridaJo (author)2017-01-15

Excellent. Thanks for giving a way to get started.

steve000 (author)2013-07-28

hahaha gross. Technically its uber beneficial but I think most people wouldn't eat it. Great and well detailed article 10 thumbs up :P

Algaescientist (author)steve0002013-07-28

I'll add some recipes to see if i can change your mind! =)

steve000 (author)Algaescientist2013-07-29

:O ok im up for that.

I see algae as fuel not food but id could never grow it enough to fuel my life so I guess i could eat it instead. Not like im gonna eat sunflowers or jatropha.

JacobS160 (author)steve0002016-11-11

Really, no sunflowers for you, eh? You should try more things. All parts of the sunflower are useful for a home garden.

Crude-pressed sunflower oil is a great dressing, the olive oil of the north (and unlike crude cottonseed oil, it's not a spermicide). The leftover meal can be used like any other nutmeal, adding a nice flavor to baked goods (almost identical to peanut) or else just used up in burgers or other protein patties (e.g. tofu if you're vegetarian).

The hulls and leaves make a great mulch, especially together. Using leaves as mulch adds trace-nutrients to the soil in much the same bioactive forms needed by plants, and sunflower hulls are tough and fibrous, giving body and physical structure to the soil to help it retain water and stay moist. I've also heard tell they're allelopathic (meaning that they help prevent weeds from sprouting).

The stalks, left connected to the roots in the garden, make great trellis poles for next year's beans and peas. (You should be rotating your garden crops anyway to take advantage of the differing nutrient requirements/additions provided by different plants; and legumes in particular are good to rotate around due to their nitrogen-fixing capacities.)

InTheory (author)Algaescientist2013-09-19

Please add recipes, I am wanting to start a home farm and this looks like a great food stuff to invest in. When I have the start up cash I will probably end up eating this stuff by the truck load :P

DrCath (author)InTheory2015-02-07

InTheory, follow this link for recipes with spirulina :)

JordanC75 (author)2016-07-08

Thanks for the post. I just wanted to provide an update on affordable starter culture for anyone trying to do this affordably. A simple trip to ebay tells me that I can beat the price given for the product you linked. Here is a link to the search results on ebay.

MBogacz (author)2016-06-21

A scientific paper from Indian Agricultural Research Institute, called Formulation of a low-cost medium for mass production of Spirulina, says: "Spirulina, being a non-diazotrophic cyanobacterium
requires nitrogen in the medium, which is generally
provided in the form of NaNO3."

MBogacz (author)2016-03-13

Thanks for this instructable! Just began collecting everything to start my own farm, but one thing is pretty unclear to me - chelated iron. Could you please write what sort of it do you use?

I found many different brands and forms (fertilizers for different sorts of cultivation, for humans) with different concentrations, addons like nitrogen, and so on. And even more confusing is that most popular medium for Spirulina (Zarrouk’s medium) uses EDTA, but I found out that for different pH you need different sources of iron: for pH lower than 6.0 EDTA is ok, but for pH 6.0–7.0 you need DTPA or HEDTA, and for pH higher than 7.0 you need EDDHA or EDDHMA. That means Fe-EDTA is not a best source of chelated iron and yet they use it. Do not want to experiment at the very beginning...

rockitaki (author)MBogacz2016-06-21

It's my understanding that Spirulina uses atmospheric nitrogen. I haven't heard of it utilizing nitrogen in solution.

ThibaultM (author)2016-04-22

If I just want to use this for oxygen generation and I don't add the harvesting tube. Would that be a problem?

lukemarq (author)2015-04-10

You answered my prayer for an instructible on this! Yay!! Thank you! I am great at predicting the future and pond scum as I affectionately call it, is in it. I have some lab grown blue-green "clean chlorella tm" and it tastes quite good. I already tried growing it but they are dead as the cell walls are all cracked for digestion. Algae can be excellent as chips (go ahead and steal that 100 million dollar idea I have a million of them). Cooking with algae requires a different mindset as slime is not a usual cooking component but I have just thought of many recipes. As powder it is a good seasoning for many things. I look forward to doing your instructible! <3

lukemarq (author)lukemarq2015-04-10

the discussions in the comments here I dare say is probably the best source of info on algae cultivation available on the net.

DrCath (author)lukemarq2016-03-25


We just added a Forum section to our website... A lot of good discussion going on there too.

OnurS3 (author)2015-11-01

is it mix nutrients working ? Because in here, one of our university prof, against that mix. She dont want to share his nutrients mix.

Any one try it ( 1.4 KG of saltpeter, 50 grams of ammonium phospahte, 30 grams of potassium sulfate and 20 grams of epsom salt. )

DrCath (author)OnurS32016-03-25

you can find the full recipe to grow spirulina here

DrCath (author)OnurS32016-03-25

you can find the full recipe to grow spirulina here

DrCath (author)OnurS32016-03-25

you can find the full recipe to grow spirulina here

DrCath (author)OnurS32016-03-25

you can find the full recipe to grow spirulina here

LisaH40 (author)2016-03-04

After harvesting and dehydrating, what would be the best way for long term storage with max nutritients retained? Canning it in the oven, mylar bag with oxygen absorber, or vacuum sealed bags

DrCath (author)LisaH402016-03-25

The best way is vacuum pack. Avoid heating spirulina as it denatures certain enzymes.

Cheap but very good guide that talks about it here

Sufferingnomad (author)2015-11-28

After harvesting spirulina will the water grow more or do you have to buy another starter culture?

DrCath (author)Sufferingnomad2016-03-25

You should never harvest more than 1/3 of your tank. Always keep 2/3 of the spirulina in your tank so they can grow over and over again and you can keep harvesting it for ever :)

You can build a super easy secchi disk with a chopstick and a yogurt container to know how much spirulina you have in your tank. (here is how to do it :

maybe lil bit late...
after harvesting you still have least culture in the aquarium, so you have to adding the water with nutrition solution to desired level...

HenriL10 (author)2016-03-17

in the order of milliseconds between illuminated and dark zones have
been shown to reduce light inhibition and increase biomass productivity (Ogbonna and Tanaka, 2000; Janssen et al., 2001). "


CarolB56 (author)2015-12-03

I live on solar power. I need everything to work dc current. 12 volt. It will need to plug into a cigarette lighter.Also what about cloudy days? Do you need a extra light? Also feeding this, can it be done if you cant buy its food source.I dont like to reley on anything i have to buy all the time to keep it alive.

alexjharvey (author)CarolB562015-12-27

You can use wood ash in place of the nutrient mix for something more sustainable off-grid. You'll just need to keep an eye on the Ph level.

shashank95 (author)2015-10-13

What all things needs to be added to the tank for the nutrition of the algae ?

TomH46 (author)2015-09-23

Can you grow spirulina at room temperature?

Algaescientist (author)TomH462015-09-28

yes, indoor spirulina cultivation is maintained at room temperature.

EjderY (author)2015-03-31

Eeating is not only about getting the needed nutrients.

Maria89 (author)2015-01-21

I'm interested in starting my own spirulina farm. Would it be safe to just drink the spirulina water right out of the tank? I would like to use the water for smoothies as opposed to running the spirulina water through a cloth. I know I would have to replace the water to get it back to the same level but other than that... Would this work and would it be safe to drink?

DrCath (author)Maria892015-01-26

no, no no, you shouldn't drink the spirulina culture medium. It's nutrients for your little blue-green algae but it's not fit for you. You need to wash them (usually 3 times) with fresh water - you can recycle the water of course and add it to your ponds - before you can consume it.

More info on the culture medium here:

Hope this helps! let us know how it goes :)

DrCath (author)DrCath2015-02-05

link above not working. Please use this link:

Maria89 (author)DrCath2015-02-06

Thank you! I was using Google to try and find an answer but I didn't find any... And thank you so much for the link! It's really helpful. I will start buying the equipment and supplies over the weekend and hopefully I will have my own little spirulina tank pretty soon :)

DrCath (author)Maria892015-02-06

Glad it helped :)

yousaf.m.shaikh (author)2014-10-07

Great instructable! One question though; you mentioned (in some of your replies) having multiple aquariums for greater yields. But what if you just used a bigger aquarium? Wouldn't that yield more spirulina? Ultimately, I'm looking to produce 3 to 4 tablespoons daily. I'd prefer working with only one aquarium and I don't mind if it's bigger. Any recommendations?

DrCath (author)yousaf.m.shaikh2015-01-26

it depends of the shape of your aquarium and the location of your culture.

Spirulina will need a LOT of light to have a high yield but if you live in the tropic (like me) the sun can damage the cells.

More info on the impact of the light on our favorite cyanobacteria here:

So in temperate latitudes you want to have an aquarium that exposes the spirulina to a maximum of light => you'll need a aquarium with a SMALL light path, think skinny aquarium, tall and long, so there is no zone in the aquarium more than 15 cm away from the sun light (or any artificial light devices you use).

In latitudes with higher sun intensity, you want to protect your spirulina from too much sun and you also want to increase the VOLUME of the tank to increase the buffer capacity of the water so the temperature doesn't go up too much (and drop down too fast, spirulina does NOT like rapid swing in temp.)

The advantage of have 2 aquarium vs. 1 is that is something wrong happens to one, you can always re-start from scratch using the other aquarium to inoculate (= introduce the spirulina into) the first one.

If for what ever reason you can only have 1, then make sure you keep a back-up culture, just in case.

A culture pond, once up and running, yields about 6 to 10 gr of dry spirulina per square meter per day. (Yields are estimated usually for larger productions that use ponds with a standard depth of 15 to 20cm, only the surface of the pond is taken into consideration for the production, so it's a little bit more tricky in a aquarium).

So to answer your question: YES a bigger aquarium will have a hogher yield.

Never weighted a tablespoon of fresh spirulina (what % of humidity are we talking about? Just as it comes out of the harvest cloth or pressed?). Let's assume it's about 10 gr, non pressed.

If you want to yield daily 40 gr of fresh spirulina @ 100% humidity, with the right sun exposure, temperature and shape, I guess you'll need a tank of about 30-40 gallon.

If you want my 2 cents, start small and then upgrade gradually towards a larger system. You can always re-sell the smaller tank and other equipments you don't want / need anymore.

I hope it makes sense :)

DrCath (author)DrCath2015-02-05

Sorry guys - I updated the website and all the links have changed :(

here is the link to the same page in the new website

Sorry for the inconvenience...

omnibot (author)2013-07-25

Spirulina is not a superfood. As far as I've seen there is no evidence of any health benefits, in fact it is toxic.

Algaescientist (author)omnibot2013-07-25

Hello Omnibot,
Do you speak from experience or just a vague google search? I have personally been consuming fresh spirulina for the last two years with positive benefits to my health and energy levels. Your link mentions pharmaceutical companies that were trying to rip people off by selling it at 300 dollars a pound. Yes, algae can become toxic if you grow it in contaminated water. The same way that if you grow a vegetable in lead contaminated soil, it will be toxic. That is why people question commercial sources of spirulina, but if you grow it at home you know the purity of your water source. As far as the term superfood, there is no consensus on its exact definition and I use it to convey the efficiency as a solar energy collector and oxygen producer in a small space. Algae as a food source produces oxygen and CO2 sequestration while most other food sources require fossil fuels to make and transport.

stoopid2 (author)Algaescientist2013-07-25

perhaps you could confirm that those nasties mentioned in the article are killed by the ph of 10?
i have been a tablet and capsule consumer from many different sources for over five years off and on. when i am flagging i start and pickup noticeably in a day or two.
except with my most recent capsule purchases from a supplier i think has gone bad or changed hands. these recent capsules also fail to turn the water into purple blue hue that i had always tested for in the past.

DrCath (author)stoopid22015-01-31

Ah ah! that's a very good indication that the
phycocyanin (one of the most important pigment of spirulina that has that deep blue hue) has been removed
and hence the efficacy of spirulina to boost your immune system greatly

Beware of cheap spirulina, that's often what happens!! This is another reason to grow your own spirulina! At least you know exactly what you're eating :)

check this for more info on the
pigments in spirulina:

And YES the majority of potentially
dangerous bacteria can not survive in a culture medium with a pH >10

So make sure you check the pH before
EACH harvest.

And BTW, you have THOUSANDS (!!) of
scientific research papers published in very prestigious journals that have
demonstrated the positive impacts of spirulina on human (and animal) health.
But most of the big pharma companies are not too happy about that.

Just go to PubMed
( and do a search for spirulina + "what
ever aliment you think it can help" and see what comes out.

But of course if you don't know what
you do and don't take care of your culture you might get nasty stuff in it,
just like when you don't brush your teeth, you'll get nasty stuff in your mouth

bpfh (author)omnibot2013-07-29

What the Quackwatch article was promoting was the companies that are selling this product as a medicin rather than as food, and then classifying it as food but selling it in medicinal quanties at medicinal prices!

Now, a part from that, there is a very valid point in this article: in the wild, you avoid eating any blue-green algae, as yes, there is a real risk of poisoning. What I do not like about this is that you start growing your algae, but it can be so easy to grow somthing else that could make you sick. With a plantation, you can pull out the weeds and keep the veggies, but here you cannot tell the difference between good and bad. As much as I believe that algae based products are good for you and in some cases wiil be a staple of the future, I would want clear testing guidelines to make sure that the algae I want to grow is actually what *is* growing... clean and fresh water is one thing... but it's not a guarantee !

AlgaeEnthusiast (author)bpfh2014-09-23

I have been growing and eating my own Spirulina both indoors and out for many years, with continuous microscopic monitoring. If you maintain the alkalinity of the medium, it is rare for other species to grow (most often Chlorella, which is harmless). Spirulina itself has never been known to produce toxins (see Wikipedia, there is a reference there). It is important to check your culture with a microscope occasionally.

InTheory (author)omnibot2013-09-19

I believe Spirulina is a superfood as the term is ill defined. It can be grown cheaply and replace 60% of your protien intake without any ill health effects. This should be a cash crop that should be up there with corn (maze). It is a complete protien that has more protien then all other usual plant sources.
Yes, don't grow it in rancid water. Don't go harvesting it from nature with who knows what in the water. However, in a tank at home where you can control everything should have no toxic ill effects.

My research
Chamorro-Cevallos, G.; B.L. Barron, J. Vasquez-Sanchez (2008). "Toxicologic Studies and Antitoxic Properties of Spirulina". In Gershwin, M.E. Spirulina in Human Nutrition and Health (CRC Press).

clibanarius (author)omnibot2013-07-28

Omnibot, according to your link, Spirulina is nontoxic, but other blue-green algae had detectable levels of a particular toxin.

Algaescientist (author)2014-02-04

So sad how people resort to name calling and accusations. The idea of sharing is only hindered by those wanting to take credit and make profit. Why can't different sources of information exist without jeopardizing the growth of each.

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