It’s a lot easier to grow your own spirulina than you might imagine, and it will give you a regular supply of spirulina with all of the benefits described on this site, for your shakes, stews and other food.
Once you have decided to grow your own spirulina, these are some of the steps you will wish to plan for:
Collect the necessary equipment and materials you will need
Stage 1. Collect or buy an aquarium tank, a small net for harvesting, an aquarium thermometre and a fine cloth. Unless you live in a very warm location with daily outside temperatures of between 22ºC and 32ºC (80-85 F), you will also need an aquarium heater.
Stage 2. Once you have set up your aquarium with clean water and fertilizer,obtain your spirulina cultures. We recommend you do not order the spirulina cultures before you have your tank set up, as they need to be placed into the prepared tank, as soon as possible after you have received them. They should not be left lying around for days until you have received and set up and fully prepared your aquarium with clean water and fertilizer.
How to grow your own spirulina – the detail
Collect or buy an aquarium tank. A tank of 54L (60x30x30cm) ought to provide a family of four with a good supply of spirulina. But equally you can use a smaller or larger aquarium tank if you are looking to produce less or more than just for yourself/family.
Whilst you can grow spirulina in a pool or pond outside, you will need to ensure you have an ambient or average temperatures of 22ºC to 32ºC. Even if you live in a warm climate, it’s probably easier for you to manage the spirulina cultures with a standard sized aquarium tank inside
Remember you need to ensure you can maintain a temperature of between 22ºC and 32ºC which in colder climates you can easily do, using an aquarium heater. Don`t forget to obtain an aquarium thermometre too.
Get a lid for your tank.
To prevent any contamination going into your tank and being soaked up by the spirulina as it grows, you also need to ensure the aquarium has a lid/cover. You can buy a more expensive aquarium, with a manufactured lid, or you can improvise. Just be sure, that no contamination, dust, dirt etc., gets into the tank from the room it is growing in.
Prepare and position your tank
Prepare your tank. It needs to be positioned somewhere warm, ideally with good sunlight. The window in your house that receives the best sunshine. Spirulina requires plenty of light and warmth to grow well. Its essential to get this right. e.g. at 18ºC (64ºF) the growth rate is only about 50% of 20ºC (68ºF). But at between 22ºC and 32ºC (72º F and 89ºF) the growth rate can double. Whilst at temperatures of 37ºC (98ºF) it may start to be damaged. And if its above 44ºC for a number of hours, it will probably die.
Add the Water to your tank.
Ensure the water you use in the tank is clean. Its essential you do not use chlorinated tap water. If however you only have access to tap water, then you should ensure this is de-chlorinated using supplies from an aquarium shop. You can run normal tap water through a standard tap filter (such as a Brita or other filter) but we recommend using bottled mineral or distilled water.
Continuing to set up your tank
- Now check the temperature of the water and set up a system to check this regularly. The temperature in your tank should ideally be around 35°C (95 F). Below 20ºC (68ºF), growth will be very slow.
- Above 38°C (100.4 F) is too warm. We recommend you use an aquarium thermometer to ensure your tank maintains the right temperature for your spirulina. Spirulina can survive or tolerate lower temperatures but it tends to thrive in warm environments. If your tank is too cold, you will need to order an aquarium heater or buy one from your aquarium supplier or pet shop.
You will also need some equipment to harvest your home, grown spirulina. Whilst a colony of spirulina can appear quite thick, its mainly water. Once it is ready to be consumed, you will need to squeeze out the excess water. Most home growers will only require a small amount of spirulina at a time, for which a small aquarium net, to scoop out the spirulina and a fine cloth, to squeeze out the excess water, should be more than adequate. For larger amounts, you will need more cloth to make it easier.
Once you have set up your tank.
- Obtain your spirulina cultures:
To kick start your spirulina colony you will need some live spirulina culture to start it off. Spirulina acts a bit like a sponge and soaks up anything in its environment, so you will want to obtain these from a trusted source to ensure the original cultures are not contaminated in any way. The Healthy Algae kit is recommended by many buyers. And the Healthy Algae fertilizer also comes recommended by them. This spirulina algae culture, comes with clear information giving advice on how to grow your spirulina algae and the company have a good customer relations reputation.
b) Once the water is in the tank, add the fertilizer food following instructions.
We find it easier to use Healthy Algae fertilizer. Alternatively, if you are a more experienced Gardner, you may wish to experiment. You will need the following:
- Citric acid
- Calcium chloride
- Sodium bicarbonate
- Magnesium sulphate
- Potassium nitrate
- Iron sulphate
- Ammonium sulphate
However, to start your colony, like us, you may find it easier to use the all in one fertilizer
Organic Spirulina Growth tips.
If you do not like the idea of adding fertilizer to your spirulina, we are currently preparing information on the best way to produce more organic spirulina, which we will be adding to this site soon.
Add the Spirulina Culture
Once you have everything set up, the tank, the water, the fertilizer, now you can add the spirulina “starter” culture. Follow the instructions on the package.
Monitor the growth of your spirulina.
Initially, its likely that your spirulina culture will seem quite thin, but slowly over time it will thicken and increase in density. Generally, you don`t have to do much other than to observe it growing. However, if the spirulina does not seem to be growing well, you can check the pH of the water using pH test strips that you can usually obtain in your local aquarium shop or on-line – be very careful that you do not contaminate the water as you conduct the test.* pH 10 is the ideal level.
Use an aquarium pump or stir the water occasionally
For best results, use an aquarium pump to ensure your spirulina thrives.
However, alternatively, to save money and to ensure your spirulina receives an adequate supply of oxygen, you can stir and agitate the water periodically. Be very careful when you do this, not to contaminate the water. A clean wooden or sturdy plastic spoon, used just for this, would probably be best.
When can I start to consume my spirulina?
If you have followed all of the instructions carefully, typically, after about 4 -6 weeks. Scoop some spirulina out and then using a fine cloth, squeeze out the excess water. Then, use the spirulina paste in your smoothie, stew or other food preparation.
Each time you take out any spirulina to use, you must remember to put some more fertilizer into the spirulina tank to ensure your spirulina culture continues to flourish. If you take a spoonful of spirulina, add a similar sized spoonful of fertilizer to the tank and stir it into the water.
Check the temperature regularly. We recommend daily.
If you are not using a pump, ensure you gently stir the water periodically, being very careful not to add any contaminants e.g from a dirty spoon into the water.
*If the pH is low, you can add a little sodium bicarbonate
(NaHCO3). To decrease the pH of the water you can add a few drops (i.e. a little) of vinegar.
For more detailed instructions, this pdf (1) may also be helpful to you.
We hope you find this page with advice on how to grow spirulina helpful. We look forward to receiving any questions you may have and hope you will start to grow your own!
Check Spirulina FAQs here.
*Nothing on this website should be interpreted as personal medical advice. Always consult a qualified Doctor or health care professional before changing anything related to your healthcare.
*Please visit our About page to see the references*
(1) Grow Your Own Spirulina by Jean-Paul Jourdan