How to Grow Your Own Spirulina

Spirulina is likely the most nutrient-dense food on the planet. It’s also been shown to have many health benefits. In fact, the United Nations declared spirulina “the best food for the future” at their World Food Conference in 1974. This is one food that may truly deserve the title of “superfood.”

You can buy spirulina supplements and powders commercially, although these are often extremely expensive and there may be potential health concerns related to them.

An excellent way to skip the high cost and questionable quality is to grow your own. The process is no harder than keeping a fish aquarium. And you’ll be able to harvest fresh, affordable, ready-to-use spirulina right from your home.


Spirulina is a type of blue-green microalgae that naturally grows in warm, alkaline lakes. It was traditionally eaten by ancient Aztecs and other Mesoamericans as well as many cultures in Africa.

Spirulina is a nearly perfect source of nutrition. Some of its nutritional highlights include:

  • Contains all essential amino acids, making it a complete protein.
  • High amounts of polyunsaturated fatty acids, such as alpha-linoleic acid (ALA) and docosahexaenoic acid (DHA).
  • One of the few known food sources of gamma linoleic acid (GLA), which is needed to regulate your hormone system.
  • Rich in many B vitamins and vitamins A, C, D and E, as well as iron, magnesium, selenium, potassium and many other minerals.

Due to its outstanding nutritional value, various international organizations currently help to establish small-scale production of spirulina in impoverished communities throughout the world to combat malnutrition and promote local food security. Another benefit of spirulina is that it requires minimal resources to produce. As it grows in water, it doesn’t need fertile land. It doesn’t even need much water because you can reuse the water it grows in.


The equipment you’ll need to grow spirulina is fairly straight-forward. If you want to simplify the process, you can buy spirulina growing kits that come with everything you’ll need. Otherwise, you can gather the following items on your own.

1. Tank

You can grow spirulina in any container, depending on how much spirulina you can use. Good options include a large jar, an aquarium tank or even a pool in your back yard. Spirulina needs light to grow, so it’s best if your container is transparent.

2. Culture Medium

Spirulina only needs water and nutrients to grow. It requires water that is very alkaline with a high pH. You’ll be adjusting the pH yourself (we’ll discuss the process below), so you do not have to use especially high-quality water. You can use water from a creek, brackish water, de-chlorinated tap water or rain water. As long as your water isn’t polluted with heavy metals or other toxins, it should work fine.

3. Spirulina Starter Culture

If you happen to know someone who grows spirulina, you can take a portion of their culture to start your own. You can also check your local health food store or find a company online that sells spirulina culture. It typically comes in a bottle with live spirulina in water.

4. Stirring Device

Spirulina needs to be stirred to maximize light reaching the entire growing culture. You can do this periodically with a stick or long spoon, or install a pump with a bubbler.

5. Harvesting Equipment

You’ll need some kind of screen with a very fine mesh of 50 microns in diameter or less. This is used to strain the spirulina out of the water. Natural silk cloth works well, or some aquarium nets have a fine enough mesh. A large cup is also handy to scoop the water into the mesh.


1. Set Up Your Tank and Starter Medium

Whatever container you’re using for your spirulina, make sure it has good light. Indoors, it can live in front of a window or you can use grow lights above it. Outside, try to position it in a bright area that’s out of direct sun.

Check out the Ice Age Farmer’s great video on setting up your tank and starting your culture below. His recipe for the starter medium nutrient mix is here on his website. You can also buy pre-made starter nutrient mixes online.

2. Check Your pH

The pH of your starter medium should be between 8 and 8.5. Litmus paper is the best way to measure your pH. It can be found at most pharmacies or natural food stores. Dip the litmus paper into your solution for 2 to 3 seconds. Once the color on the litmus paper has changed, compare it to the guide on the box to determine the pH. If the pH is still too low, add more baking soda. If it’s too high, add a bit of vinegar.

3. Add Your Spirulina Culture

Pour your spirulina culture into the starter medium and stir gently. Make sure your starter medium and spirulina culture are both at the same temperature. This helps prevent the spirulina from going into shock at too much of a temperature difference.

4. Water Your Spirulina

Water will naturally evaporate over time, so you’ll need to keep it topped up to the same amount you started with. Otherwise, your pH or nutrients can come out of balance. It’s helpful to make a mark on the side of your container once your starting culture is all done so you can see your initial amount. Then simply keep adding water if you ever see it drop.

5. Keep Your Spirulina Warm

Spirulina is naturally from tropical lakes, so it prefers warm water. It will grow in temperatures between 55 and 100 degrees Fahrenheit (13 to 38 degrees Celsius), but the ideal temperature is between 89 to 98 degrees Fahrenheit (32 to 37 degrees Celsius). Your spirulina will grow at colder temperatures, it will just be slower. If you want to maximize the growth, consider installing a heater in your water. Just make sure it does not get over 104 degrees Fahrenheit (40 degrees Celsius), as this will start to kill the spirulina.

6. Enlarge Your Culture if Needed

You can repeat the previous steps to make your culture larger if you’d like. After making your initial culture, wait at least 3 days for the spirulina to grow and establish a good population. You should see the culture becoming greener as the spirulina replicates. Then mix up a new batch of starter medium and add it to your main spirulina culture. You can do this a few times if needed until your container is full.

7. Harvest Your Spirulina

As spirulina grows, the pH of the entire culture will rise. This is the primary reason why it’s typically very safe to eat spirulina, because almost no other organisms can actually live in such alkaline conditions. To ensure your spirulina is safe, wait until the pH of your culture has reached 10 or higher before harvesting it.

After about 3 to 6 weeks of growth, your spirulina should be ready to harvest. And harvesting is as simple as scooping some of the culture’s water out and running it through your mesh cloth or net. The spirulina will collect on the cloth. Gently squeeze out any excess liquid to avoid consuming the alkaline water. You’ll be left with a deep green paste.

8. Feed Your Spirulina

Each time you harvest some spirulina, you’ll need to replenish the nutrients in the main culture. For example, if you take out 1 tablespoon of spirulina, you’ll need to add 1 tablespoon of a nutrient mixture back into to the culture. The Ice Age Farmer has a good nutrient mix on his website, or you can buy a pre-made nutrient mix from spirulina suppliers.

Spirulina drink


1. Eat It Fresh

Fresh spirulina is much tastier than most store-bought powders. Spirulina growers claim there is no comparison between the two. You can add fresh spirulina to your favorite dishes, spread it on top of fruit or bread, use it as a condiment, mix it into dips and spreads, or simply have a spoonful plain or in juice as often as you like.

2. Preserve It

Fresh spirulina is very delicate and perishable. It should be eaten or preserved within one hour of harvest. It will last about three days in the fridge, and indefinitely when frozen. It can last up to a year when dried.

To dry spirulina, spread it out in a thin layer on a flat surface. It’s best if you can spread it on some kind of net for better air flow, but a baking sheet or something similar will also work. Alternatively, use a nylon bag with a small hole or a large syringe to create thin spirulina “noodles” to dry.

You can dry your spirulina outside in the sun for about 2 days. You can also use a dehydrator or an oven set on a low heat.

Check out the following recipes for using either fresh or dried spirulina.

Related at Care2

Biologigaragen Spirulina, via Flickr


Ingrid A
Ingrid A17 days ago

thank you very much

hELEN h29 days ago


Greta L
Greta Labout a month ago

Thanks for posting

Tabot T
Tabot T2 months ago

Thank you for sharing

Jan K
Jan S2 months ago

Thank you for sharing

Frances G
Frances G4 months ago


Ruth S
Ruth S4 months ago


Renata B
Renata B5 months ago

But is this a joke? Was it written on the 1 of April? Well, I have no idea what involves to keep an aquarium because I am against the very idea of entrapping fish (who are clearly not pets) into a tiny space for all their lives, however I can say for sure that what the article suggests is far away from simple and easy. You need the right place, the right tolls (many and expensive) a lot of time and the desire/inclination to do such a thing. Considering the cost of the gadgets and the waste due to inevitable mistakes one makes, it will take you many years before you offset the cost of buying spirulina ready made. Always in the hope that at some point you give up and throw everything away. And who has the right space at the right temperature? How do you achieve that. A normal garage (and not everyone has one anyway) is not enough. We have a garage and a shed (and little greenhouse) but nothing would be suitable. Or do you think one should install some sort of 24/7 heating system with electronically controlled temperature? Sorry but this is bu*shit, I find it even borderline offensive.

michela c
michela c5 months ago

(but I usually buy it)

michela c
michela c5 months ago