How to grow algae: 10 steps (with pictures)

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How to grow algae: 10 steps (with pictures)
How to grow algae: 10 steps (with pictures)

Algae are aquatic plants that grow thanks to the nutrients in water and solar energy. People grow many different types of algae, which have a variety of uses in their daily lives. Different types of algae are grown for different purposes: for food or as a source of biofuel for trucks. One of the benefits of growing algae is that it is a fairly straightforward and straightforward process.


Part 1 of 3: Prepare your growing medium

Grow Algae Step 1
Grow Algae Step 1

Step 1. Choose a transparent container so that the light hits the algae

A glass or plastic container is perfect for this purpose.

If you're growing algae for a science exhibition, get a plastic bottle or something larger, like a small aquarium

Grow Algae Step 2
Grow Algae Step 2

Step 2. Fill the container with water

The culture medium will mainly consist of sterilized water. Pour the water into a clear container.

  • Use sterilized salt water to grow microscopic algae.
  • To grow spirulina, you should use clean fresh water. Take water from any source, such as tap water or bottled water. The main thing is that it is filtered with activated carbon or through a ceramic filter.
  • If you are concerned about bacteria, boil water before use to reduce contaminants.
Grow Algae Step 3
Grow Algae Step 3

Step 3. Add nutrients to the water

In nature, algae live together with other aquatic life. These creatures create balance in the underwater ecosystem and provide them with ample amounts of nutrients such as nitrates, phosphates and silicates. Since the water bottle does not contain these nutrients and trace elements (such as trace metals and vitamins), you must add them yourself. Buy them from the store, or take some water from an aquarium or pond and add to a container.

  • Water from a pond or aquarium can contaminate the nutrient medium with various particles.
  • Nutrient salts can also be added to the container. Find a nutritional formula that works for most types of algae.
  • Analyzing the effects of different nutrient mixtures on algae may be one of the topics of your scientific exhibition.
Grow Algae Step 4
Grow Algae Step 4

Step 4. Find a sunny spot

Before adding the algae to the bottle, find a suitable place for it (a windowsill or sunny spot in your yard where you can safely leave the algae). This will allow the algae to receive enough sunlight to grow in a nutrient medium. If you can't find a suitable place, place a container of algae under the phyto lamps.

  • Learn as much as you can about your algae to determine which lighting is best for optimal growth. Conventional plant lamps are not very effective for some types of algae. Find a lamp that will primarily emit light in the red or orange spectrum.
  • Different types of algae require different amounts of sunlight, and excessive temperatures (over 35 degrees Celsius) can even kill them.

Part 2 of 3: Add the seaweed

Grow Algae Step 5
Grow Algae Step 5

Step 1. Select the type of algae

According to the latest estimates, there are now about 70,000 species of algae in the world, and this is not counting those that have not yet been classified. People use different types of algae for many different purposes. Many types of algae are used to produce biofuels that power electrical components. Other types of algae, such as spirulina, are used in food. Sometimes algae are grown in schools or for scientific experiments. The choice of algae depends entirely on the purpose for which you need it.

  • For example, if you want to include algae in your diet, start growing spirulina.
  • Spirogyra is sometimes used in science exhibitions.
Grow Algae Step 6
Grow Algae Step 6

Step 2. Take a sample of the algae

For a simple experiment, you can take any sample of algae and observe their further development. If you just want to observe the development of algae in general, take a sample of algae from a pond, lake, or other natural source. Remember that there are many different types of algae in nature. If you want to study a particular species, take a sample from the appropriate location. In this case, it is best to purchase a specific algae species or algae culture from an algae company or order them online.

  • For example, many people are interested in growing algae such as spirulina. Since it is often used in food, purchase a sample from a reputable company.
  • If the algae is needed for a school project, take a plant sample from a local pond.
Grow Algae Step 7
Grow Algae Step 7

Step 3. Add algae to the nutrient medium

Once you have chosen the type of algae, simply add them to your culture medium. Make sure the selected algae get enough sunlight. Wait for the algae to grow.

  • It will take several weeks before the algae can be seen. This is because most types of algae (called microscopic) cannot be seen with the naked eye. For a person to be able to see them, there must be a lot of algae.
  • If you are growing a type of macroalgae such as kelp, it will be much easier to spot them.

Part 3 of 3: Keep track of algae growth

Grow Algae Step 8
Grow Algae Step 8

Step 1. Pay attention to the color change in the nutrient medium

As it grows, the algae will begin to take up more and more space in the container. The denser the algae grows, the dimmer the water will become. Most varieties of algae are green, but they also come in other colors.

  • For example, algae called "crimson" are red in color.
  • Keep a record of all changes in algal growth.
Grow Algae Step 9
Grow Algae Step 9

Step 2. Add nutrients as needed

For a short experiment, it is enough to add nutrients only at the very beginning. If you want to grow them for a long time, nutrients must be added with each new batch of algae. You should also add nutrients as the algae builds up. If you are unsure of when and how much to add nutrients, consult a health professional.

If the amount of algae becomes too large, you will have to transfer a little to a new container

Grow Algae Step 10
Grow Algae Step 10

Step 3. Look at the algae under a microscope

If you want to know more about your algae, take a look at them under magnification. Examining a drop of algae under a microscope will tell you much more than looking with the naked eye. In addition to the algae themselves, protozoa can also be seen in the sample.

If you are growing algae for a school science experiment or for work, chances are it will become part of your assignment


  • If there is too much algae, feed some plants to your fish.
  • Diary entries with photographs of algae growth will be an ideal addition to the project.
  • For optimal algae growth, you should monitor the pH and salt levels in their environment. Optimum performance will depend on the type of algae.


  • Do not give seaweed to children as they may eat it.
  • Don't eat seaweed unless it's an edible variety like spirulina.

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