Seaweeding Algae & Seaweed Growing

How to Grow SPIRULINA at Home

how to grow spirulina at home

Do you enjoy using spirulina but tired of paying huge sums for it? Grow your own supply, with our step-by-step guide for how to grow spirulina at home. It’s easier than you might think.

Spirulina is one of the most popular forms of edible algae available today. Known by most as blue-green algae, it is technically a form of bacteria called cyanobacteria. Even in small amounts, each spoonful of spirulina is packed full of vitamins and minerals. However, because it is generally grown in environments where it can absorb large amounts of toxins, most people choose to grow it in their own homes.

Starting your own spirulina colony is a fairly easy and straightforward process. We explain how to grow spirulina with simple, inexpensive tools, plus tips for choosing and using a spirulina growing kit if you prefer a readymade set. Let’s get started.

How to Grow Spirulina at Home

Spirulina Growing Supplies

The first step in starting a spirulina colony is making sure that you have all of the necessary supplies. The supplies include:

  • A Clean Tank
  • Harvesting Equipment
  • Nutrients and Minerals
  • A Spirulina Culture
Fish Tank, Aquarium

There are many different ways of growing spirulina at home, but the easiest is to simply use a standard fish tank. These tanks are available at just about every pet supply store (and second-hand stores) and are perfect for generating sufficient spirulina to provide for a family of four. If you live in a place where the climate is warm, you may even want to use a larger tank, to share with friends and family.

Harvesting Equipment

As the cyanobacteria begin to grow, the water becomes murky. To the untrained eye, your quick-growing spirulina colony may appear to be nothing more than a thick slime. But, it is actually almost entirely water. In order to properly collect the spirulina, you will need to have the proper equipment to harvest and squeeze the water how of it. This means you will need a fine mesh scoop and some muslin cloth.


There are four major things needed to ensure that a spirulina colony is successful. A colony will need plenty of water, warm weather, ample light, and the necessary minerals and nutrients to survive. While it is possible to grow spirulina in plain tap water, it won’t produce the best results because of the lack of minerals.

The minerals needed by the cyanobacteria to survive include:

  • Ammonium Sulfate
  • Calcium Chloride
  • Citric Acid
  • Iron Sulfate
  • Magnesium Sulfate
  • Potassium Nitrate
  • Salt
  • Sodium Bicarbonate
  • Urea

You can buy readymade mineral and nutrient blends for growing spirulina which we suggest you do, so don’t be worried that you need to make your own using these components!

Buy A Spirulina Culture

Of course, no spirulina colony would exist without an actual culture. Because of the possibility of introducing contaminants into the colony, it’s important to begin with a proper starter culture. Rather than collecting the spirulina from a local pond, you will need to head over to your local health food store, and pick up a spirulina starter kit. This kit is essentially a bottle of water with live spirulina cells and it.

Preparing the Tank

Once you have all of your basic materials ready, it is time to start preparing the tank to ensure the optimal growing experience.

#1 Position the Tank

To survive, the spirulina colony will need plenty of sunlight, and warmth. As a result, you will want to keep it in a space that gets constant light throughout the day. In fact, it is not uncommon for many home growers to even use artificial light to increase the amount of growth within the colony. In fact, a thriving colony can grow nearly 24 hours a day.

#2 Prepare the Water

Next off, you’ll need to fill up the aquarium with clean water, and add the necessary minerals and nutrients. If you are purchasing an over-the-counter mineral mix, then you can simply follow the instructions included in the package. It is important to remember, that you should not be using chlorinated water for your colony.

#3 Monitor the Temperature

The ideal temperature for growing a spirulina colony is around 95°F (35°C). You should have an aquarium thermometer in order to monitor the temperature on a regular basis. If the temperature gets above 100.4°F (38°C) then the growth of your colony will be affected. If you live in a cooler location, then you will want to pick up a tank warmer from your local fish supply store.

#4 Add the Spirulina

Once the tank is ready, filled with de-chlorinated water, and the nutrients are added, it is time to add your spirulina starter culture. There is no need to pour the entire bottle into the tank. Instead, you will want to pour only about half of it into the tank, saving the other half for later. In the event that the colony does not survive, you will still have additional spirulina left over.

Maintaining the Spirulina Colony

Starting a spirulina colony from scratch can be an overwhelming yet rewarding experience for anyone. After you have gone through all that effort to set up your tank, it’s time to maintain the colony for years to come.

Watch it Grow

You would be amazed at how fast a spirulina colony actually grows. As a cyanobacterium, the colony itself is composed of millions of microscopic cells that multiply by splitting.

You should pick up some pH test strips from your local grocery store, in order to ensure that the pH of the water stays around 10. If the pH level is too low, then you will need to add more minerals to the tank. In just a matter of a few days, your colony should begin to bloom and it will expand rapidly from there.

Agitate the Tank

Because spirulina is a living organism, it also requires oxygen in order to survive. While not necessary, it’s best to purchase an aquarium pump to provide a steady supply of oxygen to the tank. Remember, one of the benefits of growing a colony of cyanobacteria is that it can consume large amounts of carbon dioxide from the air. A standard aquarium pump, will provide the colony with plenty of CO2 and oxygen, and agitate the tank at the same time.

Harvest the Spirulina

It will only take about 3 to 4 weeks before your colony is ready for its first harvest. If it is your first spirulina colony, then it may even take up to 6 weeks before it is ready. Using a fine mesh net, simply scoop out some of the spirulina and transfer it to a doubled-over piece of muslin cloth. You will only need to collect about a spoonful per person, per day. Any more than this will run the chance of spoilage.

Filter the Spirulina

With the help of a piece of doubled-over muslin cloth, you can begin to squeeze the excess water out of your spirulina. Gently twist and squeeze to press out any excess water, leaving you with a green paste inside of the cloth. This freshly harvested spirulina can then be mixed into a smoothie or spread on top of your favorite foods. Some people will even consume spirulina by itself.

Replenish the Spirulina Food

In the end, it is important to remember that you need to also replenish your colony. Every time you harvest some of the spirulina, you will need to also add some more minerals and nutrients into the water. That is, for every tablespoon of spirulina you harvest, you will want to add a tablespoon of nutrients back into the water.

Always make sure to monitor the temperature of the tank, to ensure that the water stays within the optimal growing temperatures. Pay close attention to the pH levels of the water, and add nutrients when necessary. On rainy days, it may also help to place an artificial light near the tank, to ensure that the colony continues to grow on a regular basis.

Choosing & Using a Spirulina Growing Kit

If creating a spirulina growing set-up from scratch is not your thing, an alternative is using a readymade spirulina growing kit instead. The benefit of a kit is that it contains almost everything you need, so you don’t need to buy these components individually.

When choosing and using a spirulina growing kit, it’s important to always make sure that you get the right equipment and a clean and safe starter kit for your spirulina colony. Here are two of the more popular options available today:

Algae Research

Visit Algae Research official website

When it comes to choosing the perfect growing kit for your spirulina colony, it’s important to choose something that includes a spirulina culture, the necessary nutrients, and minerals, as well as some basic tools needed to maintain and harvest the algae. Although there are many great kits available today, Algae Research is one of the more popular. Not only do they provide all of the basic essentials needed to get your colony going right, but they also provide you with plenty of videos and material to answer any question you may come up with a long way. Literally, the only thing their kit does not include is the aquarium, air pump, and an artificial light source.


Visit Grow Spirulina official website

For a more advanced spirulina growing kit, look no further than Grow-Spirulina. Their kit is perfect for everyone regardless of experience level. Each kit comes complete with a detailed guidebook, that provides you with step-by-step instructions to ensure you get your colony up and running with minimal effort. Best of all, the kit includes all of the growing mixes for maintaining a 40L culture, more than 750 g of minerals and nutrients, an aquarium heater, thermometer, air pump, hose, air diffuser, pH meter, harvest screen, and even a Secchi stick. As with most kits, all you need to find is your own aquarium and an artificial light source. In just over a month, you will be able to harvest your first spoonful of healthy spirulina.

Final Thoughts on How to Grow Spirulina

If you’ve been enjoying the health benefits of spirulina, you may also be noticing that it can be quite cost-prohibitive to purchase. An alternative, if you don’t mind partaking in some underwater gardening, is to grow your own fresh spirulina colony at home. Like making your own kombucha, growing your own spirulina requires some light work in the initial set-up, and thereafter is maintained to keep the spirulina colony alive.

Once you understand what spirulina is and it’s growth habit, growing spirulina is actually quite straightforward, and even easier if you decide to use a readymade spirulina growing kit. When setting up your equipment, whether using a kit or making it from scratch, remember to keep everything very clean to minimize the risk of any cross-contamination from unwanted bacteria.

Happy seaweeding!