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Is Algae Bad for Plants? (All You Need to Know)

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The plant-like aquatic organisms living mostly in water and producing their food are algae. There are a variety of algae in the environment. And they can tackle tough conditions and environments. They are found in other plants and soil as well.

Is algae bad for plants?

Algae is good and bad for plants depending upon some conditions. When present in small amounts in aquatic settings, they are not harmful. They pose harm when they outspread. And when they grow on the soils of other plants, they inhibit their growth. But you can use algae to make fertilizers. 

Algae is a water-based plant or organism. There are different types of algae. Some are useful, and some are harmful. The nature of these organisms depends on their features and place of habitation.

Green algae:

Algae, in general, grows in wet and humid environments. They are microscopic and appear in colonies. Green algae are the most common type of algae.

Green algae do not cause any harm to other plants. They make good fertilizer when used in an adequate amount correctly.

Algae can break down to produce nitrogen as they are not non-living organisms. They help make better compost and fertilizers in a short time.

But the use of algae has to be kept under control. It can cause problems if they overpower the soil or plants. It will become harmful to the plants.

Moreover, it can suck up the nutrients of other plants. And there arises a competition for survival.

Brown algae:

The common region for the growth of brown algae are marine environments. They are not plants, to be precise. They are tiny organisms known as a diatom.

These little organisms or animals are harmful to plants in some ways. If they cover any plants or corals, they can use the nutrients of their bearer. It can cause that plant to lose life due to lack of nutrition.

Moreover, brown algae cover-up plant leaves when they grow on them.

So, sunlight will not reach the plants. Therefore, that plant will not perform photosynthesis, and it will eventually lose life.

What does algae do to plants?

Algae is a versatile organism. Various algae can survive and dwell in adverse conditions. They grow in plenty of places and live according to their habitat location.

Algae can produce their food with some exceptions. Many live with the help of other organisms. This relationship of algae with other organisms is known as lichen.

Algae grow in water as they are aquatic. But many of them live in tree barks and pot plants as well.

Algae are harmful to plants as they absorb their nutrients. They can also spread and invade plant soil and make the roots rot. Due to the presence of algae in soil, the water does not reach the roots of plants and harm them.

Algae on leaves of other plants inhibit the acceptance of sunlight. It obstructs the process of photosynthesis.

But the use of algae to make fertilizer is good for the plants and soil. They make good use of it. You have to use it in proper ration and control. Systemic use of algae to help your plants is possible.

Algae often invade aquariums and pot plants. It happens when favorable conditions of growth are available for them. That is, they become more humid and damp.

They can help increase the amount of oxygen in water but covers plant leaves. It can make your plants wear out. And they can stop the internal functions of roots by covering the upper surface of soils.

So, the effects of algae in plants are twofold. They can help and harm plants. To use them beneficially, use algae to make fertilizers. And keep your aquarium and pots clean to stop an invasion.

Is algae bad for these plants?

Algae is an aquatic plant-like organism that grows in a moist environment. They can survive in diverse situations with ease.

Plants in water:

There are various types of algae. They have no roots or stems. They float in water.

Algae are not harmful to plants in water. They are useful if present in little amount in water. Excessive algae in any water body can cause harm to the aquatic as well as plant lives.

Algae live on nitrates produced by waste products in water. They can absorb that. When there are a lot of algae, it can eliminate other plants by absorbing all the nutrients.

Aquarium plants:

When ammonia increases in an aquarium, algae grow there. The nitrates from the waste of plants and fish can cause this growth.

Algae in a small amount can increase the amount of oxygen and help the fish. But it is not healthy in large amounts inside the aquarium. It can deprive other aquarium plants of their nutrients.

So, clean your aquarium water and tank to get rid of algae.

Carnivorous plants:

Algae are not harmful to carnivorous plants. They are seen on these flesh-eating plants many times. They do not cause any harm to the plants.

But the growth of algae in carnivorous plants is alarming. It represents a moist and shady environment around those plants.

They are not harmful because they feed on the organic products of the plants. They survive on the waste by-products.

Pond plants:

Algae are not harmful to plants in ponds unless they evade the pond. An excessive amount of algae is detrimental to pond plants and aquatic life.

It will outnumber the aquatic plants in the pond and take all the nitrates from there.

But few algae are good for the living organisms and the quality of water in the pond.

House plants or Pot plants:

They are common in the soil of potted plants and obstruct the airflow and sunlight from reaching the roots. They affect the plant root causing the leaves to wither and roots to rot.

Plant roots:

Algae on plants obstructs the path of nutrients to the roots of that plant. Roots take up the water and other components necessary for plants from the soil. When algae are in the soil, it affects them and leaves them bare.

So, the root cannot absorb anything. It causes the leaves and stems to wither.

How to get rid of algae in plants?

Algae are a nuisance when they grow in abundance. They start to use the nutrients of plants and organisms around.

Places with water and moist surrounding are ideal for algae. They are common in pot plants or houseplants as well.

Reducing light source:

The cultivation of different plants is famous in a hydroponic environment, without soil. These plants have a higher chance of infestation of algae as they live in direct contact with water.

To get rid of algae from these systems, you can reduce the light source before treating the algae plants. It will ensure the prohibition of receiving light to produce food by itself. And make it easier for you to remove algae with less hassle.

UVC light:

UVC or ultraviolet-C rays are good for getting rid of algae. This radiation is costly and needs powering as long as the system runs. But they are effective in case of treating a lot of algae.

You can use UVC light in your hydroponic system for better results.


Algaecide is one kind of biocide. They can help you get rid of algae from plants and other places. But their use has to be kept under control.

Excessive use of algaecide can cause your other plants harm and reverse the situation. Use them according to the number of algae you want to treat. They are most effective for the early stage of algae infestation.

HTH 67032 Super Algae Guard Swimming Pool Algaecide Cleanser, 1 qt

Using bleach:

Various cleaning solutions help you get rid of Algae from fish tanks.

The species of plants you are removing the algae from is an important factor in this case.

You cannot soak your plants for more than five days in a 10% bleach solution. Some plants even require less soaking and get rid of algae faster.

Then you have to remove the algae by scrubbing it from the leaves gently. And then soak it in water solution for another 10 minutes. Then rinse the plants to get rid of the remaining algae.

Clorox HE Performance Bleach, 121 Oz. (Pack of 1)


Algae grows due to excess watering in potted plants. The wet and moist soil makes it ideal for algae growth.

It is hard to get rid of algae from pot plants. It reaches a long way into the soil. So, it is better to re-plant it by exchanging the previous soil with new soil.

The new soil has to be clean. And you have to clean the pot with a cleaning solution and water to get rid of any residues.

Final thoughts

Algae is useful to plants in providing fertilizing qualities. You can make fertilizers using algae. And few algae in water and ponds are good for the environment. But they are bad for plants when they overpower them and use their nutrients for their growth.

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