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Do I Need to Fertilize My Aquarium Plants? (Is it really necessary?)

Plants are great! They help enhance the athletic look of your aquarium. And there are a ton of benefits of keeping live plants in an aquarium.

So you got some plants for your aquarium.

But now you are wondering, do I need to fertilize the plants?

Well, this is the question I am going to answer in this article.

Keep reading…

Do I Need to Fertilize My Aquarium Plants? (Is it really necessary?) image

So, do you need to fertilize your aquarium plants?

The short answer is, YES. If you want the live plants in your aquarium not just barely survive but thrive then you most likely going to need to feed them fertilizers.

Why do you need to fertilize your aquarium plants?

Aquarium plants are living things and just like us, they require several nutrients for their proper growth and development.

If they don’t get these essential nutrients then you will see various signs of deficiencies in the plants.

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Essential nutrients for the aquatic plants’ growth

Aquatic plants require several micro and macronutrients for their proper growth

Macronutrients

Macronutrients are the nutrients that plants require in larger quantities.

The macronutrients that the plants require include 

  • Nitrogen 
  • Potassium
  • Carbon 
  • Phosphorus 
  • Calcium 
  • Manganese
  • Sulfur

Now let’s see each nutrient’s importance in the proper growth and development of aquatic plants.

Carbon

Plants require carbon in the most quantity compared to other macronutrients.

Literally, plants use approximately 10 times more carbon than other macronutrients combined.

This is why carbon is the most essential nutrient for the proper growth of aquarium plants.

Usually, carbon dioxide is the main source of carbon for aquatic plants.

And this is the reason CO2 injected tanks show very rapid and lush growth of plants.

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Nitrogen

Nitrogen is the second most needed nutrients for plants after carbon.

Nitrogen is found in chlorophyll which helps plants in the process of photosynthesis by which they produce their own food.

That’s why nitrogen is one of the most essential elements for the proper growth of plants.

If the plants don’t get sufficient nitrogen then you can see noticeable slow growth in the aquatic plants.

Phosphorus

Phosphorus is one of the most important elements for the coloration of colored aquarium plants like red aquarium plants.

If the plants are not getting sufficient Phosphorus then the leaves of the plants turn paler.

If the plants get sufficient Phosphorus then the plants show robust growth and display very good coloration.

Potassium

Potassium is one of the most essential nutrient for plants that plays a role in several plant functions.

It is one of the most essential elements for photosynthesis.

If your tap water doesn’t contain adequate potassium then the plants will start showing various signs of potassium deficiency.

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Micronutrients

Micronutrients are as the name suggests are the nutrients that plants require in very small quantities.

The micronutrients plants require for their proper growth and development includes 

  • Iron 
  • Boron 
  • Manganese
  • Copper 
  • Zinc 
  • Chlorine 
  • Molybdenum

Iron

Unlike other nutrients like nitrogen, potassium, and phosphorus, iron is not a mobile nutrient i.e. it cannot be transferred from old leaves to new leaves.

That’s why a sufficient amount of iron is essential for the healthy growth of new leaves.

Besides, iron is one of the most essential elements for the formation of chlorophyll.

If the plant is not producing sufficient chlorophyll then it will start showing symptoms like yellowing of leaves.

Manganese

Plants prepare their own food by the process of photosynthesis. And magnesium is one of the micronutrients involved in the process of photosynthesis.

So if the plant is not getting sufficient magnesium then it can result in reduced photosynthesis which can ultimately cause slow growth in plants.

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Zinc, copper, boron, molybdenum

Plants require all these micronutrients in a very very tiny amount for the proper growth and development.

Other micronutrients

Besides, the above micronutrients, plants also require hydrogen, sulfur, oxygen for their proper growth.

You don’t need to provide these micronutrients to the plants because these nutrients are usually available in tap water in an adequate amount.

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Nutrients provided by the livestock in your aquarium

The inhabitants in your aquarium like fish and invertebrates produce waste in the tank.

This waste can provide nutrients to the plants.

Nitrogen

If your aquarium contains a good amount of inhabitants like fish and invertebrates then usually the plants in your tank get sufficient nitrogen in the aquarium.

Phosphorus

If your aquarium is well stocked then usually the plants in the tank will get the required amount of phosphorus in the aquarium.

Potassium

The wastes produced by the inhabitants in your aquarium can also provide potassium to the plants. But usually, it is not adequate for the plants.

Besides, if the tap water of your region contains potassium then the plants will get the potassium they needed.

So, as you can see, the waste produced by the livestock in your aquarium does provide some of the essential nutrients to the live plants in your tank.

But to provide other essential micro and macronutrients you will need to feed your plants with fertilizer.

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What will happen if the plants didn’t get all the essential nutrients?

The plants require all the micro and macronutrients mentioned above in a balanced quantity.

And the plant will show some signs of deficiency if they are not getting a particular nutrient in your aquarium in an adequate quantity.

Aquarium plants Deficiency Diagram

(source)

Carbon deficiency

Plants require carbon in most quantity compared to other macronutrients.

And plants get carbon through carbon dioxide. That’s why carbon deficiency is also termed as carbon dioxide deficiency.

Symptoms of carbon deficiency include yellow leaves and slow or halted growth of aquarium plants.

In the case of carbon deficiency, you should supplement your plants with fertilizer that is rich in carbon like Seachem Flourish Excel. Check it out at Amazon here.

Or you can provide pressurized CO2 to your aquarium plants.

Nitrogen deficiency

Nitrogen is very important for maintaining a good growth rate of aquarium plants.

Plants usually get the nitrogen that they need from the waste produced by the inhabitants in your tank like the fish or shrimp, etc.

But if you don’t have a well-stocked aquarium or if you have a very heavily planted tank them nitrogen deficiency can occur.

Also, if you are doing the water changes very frequently then it can also remove the nitrate from the water that can lead to nitrogen deficiency.

The symptoms of nitrogen deficiency include yellowing leaves and the leaves start turning translucent.

In the case of nitrogen deficiency, there are a couple of ways you can increase nitrogen in your aquarium.

Feed your fish

A natural way of increasing nitrogen in the aquarium is by feeding more food to the fish.

When you feed the fish more the fish will start producing more waste. And this waste will get converted into ammonia and nitrate that the plants can absorb to get nitrogen.

But the problem with this approach is that it is not always a good thing to feed more food to your fish than it is necessary. Because this can lead to health issues in the fish.

Feed fertilizers

Another way to increase nitrogen in an aquarium is by adding fertilizers in the aquarium.

There are nitrogen fertilizer supplements available in the market like Seachem Flourish Nitrogen which helps to cope with nitrogen deficiency. You can check out the fertilizer at Amazon here.

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Iron deficiency

Iron is one of the important micronutrients plants require for their proper growth.

Iron contributes to the production of chlorophyll which gives plants the green coloration.

Besides, Iron is not mobile as other micronutrients like nitrogen, potassium, etc so it cannot be transferred from one part to another part of the pant.

In the case of iron deficiency, plants show symptoms such as the new growth or the new leaves of the plant will start turning yellow. And the veins of the leaves will get darker in color.

To cope with the iron deficiency, you will need to provide fertilizer to your aquarium plant that is especially rich in iron. Or best provide iron supplement fertilizer to your aquarium plants like Seachem Flourish Iron. You can check out the fertilizer at Amazon here.

Potassium deficiency

Potassium is one of the most important elements for the process of photosynthesis by which plants produce their own food.

That’s why in the case of potassium deficiency, you will see a noticeable slow or crippled growth and development of plants.

Potassium deficiency is very easy to identify. If your plants are suffering from potassium deficiency then you will see small pinholes on the leaves of the plants.

Usually, plants get potassium from tap water.

But if the tap water in your region does not contain adequate potassium then you will need to supplement your aquarium plants with potassium supplements like Seachem Flourish Potassium to cope with the potassium deficiency issue. You can check out the fertilizer at Amazon here.

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Phosphorus deficiency

Phosphorus is one of the most essential elements for the coloration of coloring plants like red aquarium plants.

Besides, Phosphorus helps with the robust growth of aquarium plants.

In case of phosphorus deficiency, the lives of the aquarium plants will start turning yellow. And there will be some brown patches on the leaves with a big hole.

To overcome Phosphorus deficiency, you should supplement your aquarium plants with phosphorus fertilizer like Seachem Flourish Phosphorus. You can check out the fertilizer at Amazon here.

Manganese deficiency

Manganese is one of the most important elements for photosynthesis.

If the plants are not getting sufficient manganese then you will see slow growth if not at all in the plants.

In the case of manganese deficiency, the leaves of the plant will start turning pale in color. And the veins of the leaves will turn darker in color.

In the case of manganese deficiency, you should supplement your aquarium plants with fertilizers that are rich in manganese.

Calcium deficiency

Though calcium deficiency is very rare because most likely the tap water will contain some amount of calcium that will be sufficient for the plants.

But on rare occasions plants can suffer from calcium deficiency.

In the case of calcium deficiency, you will notice that the leaves of the plant will be relatively smaller in size and they will be light green in color.

So in the case of calcium deficiency, you should supplement your plants with fertilizer that contains calcium.

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Fertilizer is the solution!

So, as you can see, for almost all the aquarium plant deficiencies providing fertilizers is the solution.

Types of fertilizers

Types of fertilizers

Not all fertilizers are equal because each brand of fertilizer contains different amounts of micro and macronutrients.

All in one fertilizer

There are some aquarium plant fertilizers that are known as all in one fertilizer which basically means that they contain all the essential macro and micronutrients in small quantities.

These fertilizers are useful if you don’t have a very heavily planted tank. And you just want to provide all the essential nutrients to the plants.

A particular nutrient supplement

There are some aquarium plant fertilizers that contain only one nutrient in excess quantity.

These fertilizers are useful when you notice any particular plant deficiency and you want to provide only a particular nutrient in excess quantity to cope with the deficiency.

Liquid fertilizers and root tabs

You can provide fertilizers to your aquarium plants in either liquid form or solid form in the form of tabs.

Liquid fertilizers

Liquid fertilizers, as the name suggests, are in liquid form.

You should use this fertilizer if you have aquarium plants that get most of the nutrients through their leaves from the water column.

Liquid fertilizers are relatively easy to use compared to root tabs. Because you just have to pour down the cap of liquid fertilizers into the tank on a daily or weekly basis.

However, root tabs are also very convenient in other aspects that we will talk about later.

Root tabs

Root tabs are basically fertilizer in the form of tabs that you have to insert into the substrate of your aquarium, ideally, near the roots of your aquarium plants.

These fertilizers are essential if you have heavy root feeder aquarium plants in your tank.

Unlike liquid fertilizers, root tabs are considered convenient because you don’t have to frequently add them in the aquarium.

You just have to insert the root tab into the substrate of your tank. And then the root tabs will slowly break down into the substrate and provide nutrients to the plants for 3 to 4 months.

So root tabs are kind of “set and forget” type of thing!

The ideal way

Even if you have heavy root feeder aquarium plants, still, you should supplement the plants with liquid fertilizer along with root tabs.

Because even if the plant is a heavy root feeder it still absorbs nutrients through the water column.

So for the robust growth, you should supplement it with both liquid fertilizer as well as root tabs.

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How often should you fertilize your aquarium plants?

How often should you fertilize your aquarium plants is really going to be dependent on- 

  • The plants in your tank
  • The type of fertilizer you are going to use to fertilize your plants 
  • The brand of the fertilizer you are going to use

If you are just starting out with the fertilizers then to keep the things simple choose all in one fertilizer i.e. the fertilizer that contains all the essential nutrients.

And start feeding the fertilizer according to the label.

Then wait for at least a couple of weeks to see the results. If everything looks fine i.e. plants are growing faster than usual and no signs of any plant deficiency then keep adding the fertilizer according to the label.

If you notice any symptom of deficiency then you should add that particular nutrient supplement to cope with the deficiency.

For example, if you noticed that the leaves of your aquarium plants are turning yellow and translucent then it is a sign of nitrogen deficiency.

So in case of nitrogen deficiency, you should provide nitrogen supplement to your aquarium plants.

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The best fertilizer for aquarium plants

The best fertilizer for aquarium plants

Now I am going to recommend fertilizers for aquarium plants.

Liquid fertilizer

My recommended liquid fertilizer is Seachem flourish freshwater plant supplement.

This is an “all in one” liquid fertilizer which basically means that it contains all the essential micro and macronutrients that plants require for their proper growth and development.

You should use 1 capful that equals 5 ml of the fertilizer for or every 60 gallons. And you should add the fertilizer on a weekly basis.

The cap has threads and each thread is approximately 1 ml so if you have smaller aquariums say 30-gallon tank then you should add a half cap of the fertilizers into the tank on a weekly basis.

If you have a lot of fast growing plants in your tank then you can consider adding fertilizer twice a week.

Besides, after three months of opening the fertilizer you should consider refrigerating it.

Check the latest price of Seachem flourish at Amazon here

Root tabs

I recommend Seachem flourish tabs if you have root feeder aquarium plants in your aquarium.

These tabs contain all the essential macro and micronutrients for the proper growth and development of plants.

You should add the root tab in the area of your aquarium where you have planted plants.

You should insert the root tabs halfway into the substrate snd just make sure to keep at least 5-6 inches distance between the root tabs.

The root tabs will slowly break down in the substrate and provide nutrients to the plants for 3 to 4 months.

After three to four months, you should consider adding root tabs again in the substrate of your aquarium.

Check the latest price of Seachem flourish tab at Amazon here

FAQ

FAQ
Are fertilizers safe for fish?

Yes, the fertilizers that are specially made to be used in aquariums are totally safe for fish in the aquariums.

However, there are some elements in the fertilizer that can be harmful to the inhabitants in the aquarium if you overdose it.

I have written in detail about this topic in this article.

Can aquarium plants grow without fertilizers?

Yes, aquarium plants can grow without fertilizers.

Plants require several micro and macronutrients for their proper growth.
And plants can get some of these nutrients from the waste produced by inhabitants in your aquarium and from the environment.

However, plants will not be able to get some of the essential nutrients in sufficient amounts naturally if not at all in the aquarium.
This can result in nutrient deficiency and slow growth in aquarium plants.

How can I make my aquarium plants grow faster?

To make your aquarium plants grow faster, you’ll need to provide the ideal environment and essential nutrients in a balanced amount to your aquarium plants.

Plants will get the essential nutrients naturally in the aquarium. But to encourage faster growth you will need to supplement more nutrients along with good lighting conditions.

To provide more nutrients to the plants you can use fertilizers.

Also, carbon is one of the most needed elements for plants. Carbon literally makes up 45% of the dry mass of the aquarium plants. 
And plants require almost 10 times more carbon than other micronutrients. 
That’s why providing additional carbon through injecting CO2 in the aquarium can drastically help to speed up the growth of the aquarium plant.

Besides, to absorb and keep up with all the provided essential nutrients, you’ll also need to provide higher intensity light to your aquarium plants.

Overall, if you provide more nutrients, CO2, and more light to the plants in a balanced amount then this will encourage faster growth in the plants.

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Will aquarium plants grow in gravel?

Yes, you can grow most of the aquarium plants in gravel.

However, if you want to plant heavy root feeder aquarium plants in the gravel then you will need to provide fertilizers to such plants through root tabs.

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Conclusion

In a nutshell, if you want your plants to thrive and not just barely survive in your tank then you most likely need to provide fertilizers to your aquarium plants.

Besides, plants are not able to get all the essential micro and macronutrients naturally in the aquarium and that’s why fertilizing the plant is very important.

I hope you found this article helpful.

If you do, please share it

Happy aquascaping!

Photo of author
Author
Prathmesh Gawai
He is the main author and editor at Aquagoodness.com. And he loves to share helpful information on aquarium and/or fishkeeping hobby. Prathmesh has over five years of aquarium and/or fishkeeping experience. Currently, he has a Betta fish tank. He has written hundreds of articles on various aquarium fish species and on fish tank maintenance over the last five years. Connect with him on YouTube here. Learn more about him here.

2 thoughts on “Do I Need to Fertilize My Aquarium Plants? (Is it really necessary?)”

  1. I recently moved and I’m setting up a 55g which is currently cycling. My fish are in a temp tank at my brother’s house because I had to move before my closing date. Right now I have about 20 guppies and a bunch of cherry shrimp. The guppies will go in the 55g tank once it’s cycled, and then I can start cycling the 20g for the guppies. My plans for the 55g are 12 Cory cats, 10 female bettas, 10 rainbow fish, and 12 of some type of tetras. My problem is keeping plants alive. I seem to maintain the floating plants with no problem, and the Anubis which I glue to rocks and driftwood, but the ones I plant never do well. After reading this article, I don’t think I’m fertilizing enough. I also use a fine grain sand for substrate, which I understand does not allow nutrients to penetrate through to the roots, although I do use root tabs. I just spent $200 on “hardy, easy to grow” plants, and I don’t want to lose them! But the leaves on my Amazon swords are already melting after a week. Could it be too much light? I have the LED plant light with a timer and I try to mimic a normal 24-hour cycle, with sunrise and sunset, but at “noon” I may have it too strong. Should I lower the lighting at least initially when planting live plants?

    Reply
    • It’s a good idea to lower the lighting initially and gradually increase it over time. As for plant leaves melting, some plants can take some time to adjust to the new environment and I think that’s why the leaves are melting. So in this case, just take good care of them i.e. good lighting and feeding them high-quality fertilizer and after some time they’ll be fine.

      Reply

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