Food of the Future: Window DIY Spirulina Superfood




About: Spirulina Tinkerer.

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

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

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

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

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

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

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

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

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

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

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

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

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

Step 14: Feeding

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.
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    158 Discussions


    3 years ago

    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...

    2 replies

    Reply 2 years ago

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


    Question 4 months ago on Step 14

    "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."

    Is that correct? 1.4 KG of saltpeter?? I'm pretty sure that's overkill for the KNO3. Maybe you mean 1.4 KG of sodium bicarbonate and forgot the KNO3 by mistake?


    7 months ago

    I have grown spirulina algae at home but it does not smell like the products sold on amazon. I do not understand why so.Please explain to me!

    Question 8 months ago

    Hi Sir

    I'm planning to purchase Veg- Omega 3 supplements which are made from fermentation based microalgae. Would you please throw some light in this so that I'll plan accordingly to go for this.

    Thomas sxt

    2 years ago


    Thanks for the Tutorial !

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


    2 years ago

    Excellent. Thanks for giving a way to get started.


    5 years ago on Step 13

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

    5 replies

    :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.


    Reply 2 years ago

    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.)


    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


    Reply 4 years ago on Introduction

    InTheory, follow this link for recipes with spirulina :)


    2 years ago

    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.


    2 years ago

    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."


    2 years ago

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


    3 years ago on Introduction

    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

    2 replies

    Reply 3 years ago on Introduction

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


    Reply 2 years ago


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