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Top 5 Best Aquarium Plant Fertilizer (2020 Review)

A planted tank can look breathtaking, but a little bit of maintenance is involved to get this level of beauty. Like fish, plants need a variety of vitamins and minerals to keep them healthy and this is where an aquarium fertilizer comes in.

Fertilizer provides your plants with everything they need to thrive so you can get that stunning tank you’ve always dreamed of. WIthout giving your aquarium plant food to grow, the end result is usually yellow, brown, or decaying leaves. That’s definitely not very attractive!

Finding a good formula can be a little tricky if you’re not sure what to look for. To save you some time and frustration, I’ve reviewed a lot of different products to help you achieve a beautiful planted tank.

After considering all the options our top picks were…

Review Summary

Best All-Rounder

API Tablets Freshwater Aquarium Plant Fertilizer

API tabs are an affordable but good-quality option for a natural aquarium. The tablets are slow-releasing, which means they don’t need to be replaced too frequently.

API Tablets Freshwater Aquarium Plant Fertilizer

This fertilizer is my overall recommendation for a planted tank.

These root tablets from API are an excellent choice for a planted fish tank. They contain carbon, iron, potassium, and other minerals to keep your plants healthy. The tablets only need to be changed every month, which makes for easy maintenance.

Best on a Budget

Osmocote Plus Aquarium Live Plant Tabs

Osmocote Plus root tabs are extremely affordable and keep your aquarium nourished. They’re particularly beneficial for heavy root feeders like Amazon swords.

Osmocote Plus Aquarium Live Plant Tabs

For aquarists who need quality but affordable plant food, this one is a great option.

If you’re looking for a quality aquatic plant food that’s also inexpensive, then Osmocote capsules are a great choice. They aim to keep your plants healthy and colorful.

Editor’s Choice

NILOCG ThriveCaps Root Tabs

They are a blend of dry Thrive mix, iron rich clay, and mineralized top soil. This composition contains all the necessary vitamins and minerals you need to get your aquarium looking healthy.

NILOCG ThriveCaps Root Tabs

My personal favorite aquatic fertilizer. It provides your plants with lots of minerals for optimal growth.

These capsules only need to be replaced every 3 or 4 months, so they’re very long-lasting. They contain all the necessary vitamins and minerals your fish tank requires for healthy, growing plants.

Why Should I Use Planted Aquarium Fertilizer?

If you own live aquatic plants in your tank, then fertilizer can be incredibly beneficial for their growth and health. This is especially true for certain species of plants that require a great deal of nutrients to thrive.

If you own live aquatic plants in your tank, then fertilizer can be incredibly beneficial for their growth and health…

Even for less demanding aquarium plants, food is important. Just like all species of fish need a varied diet, all plants need nutrients to reach their full potential. 

Although fish waste can assist with fertilizing your aquarium greenery, there are a lot of minerals they will be missing out on that can only be found in fertilizer. When this happens, plants struggle to grow or fail to grow altogether. In addition to this, they’ll have discolored or wilted leaves, which isn’t very appealing.

Obviously, you want your tank to look its best, so fertilizing your plants is a key method to achieving that goal.

Macronutrients

Macronutrients are nutrients like potassium, phosphorous, and nitrogen, which plants require a large amount of.

Micronutrients

As you might have already guessed, micronutrients are the exact opposite of macronutrients. They’re nutrients like boron, iron, and manganese, which plants don’t need as much of.

Planted Tropical Freshwater Aquarium with Fish
Planted Tropical Freshwater Aquarium with Fish

Types of Aquarium Plant Fertilizer

There are a few different types of fertilizer you can use in your tank, which might seem a little confusing at first. Don’t worry, they all essentially have the same purpose (i.e. to fertilize your plants), but some varieties are better suited to certain species of aquatic plants.

Liquid Plant Fertilizers

A lot of planted aquarium fertilizers come in liquid form. They’re added to your tank water directly and provide your plants with a number of nutrients.

Liquid fertilizer often contains nitrogen and phosphorus, which can contribute to the growth of algae. Algae doesn’t harm your fish or plants, but it can be a pain to eradicate and can look unsightly.

TIP

It’s typically advised to only use liquid fertilizer around once a week. This gives your plants everything they need to be healthy, but lessens the likelihood of an algae outbreak.

Pre-packed Substrates 

This type of substrate comes in soil form and contains a plethora of nutrients which are beneficial for the roots of your plants. The nutrients normally release over time, so it will be a while before you need to replace the substrate. 

TIP

Using pre-packed substrates means you don’t normally need to add any other types of aquarium fertilizers to your tank. 

Aquarium Plant Tabs

Aquarium fertilizer tabs or roots tabs are placed underneath your substrate, near the roots of your plants. They are made up of essential elements that are compressed into pill form, which slowly release over time. 

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Plant tabs work best for plants that are heavy root feeders, such as Amazon swords.

DIY Aquarium Fertilizers

Surprisingly, you can make DIY fertilizer for fertilizing aquatic plants. It’s not as complicated as it sounds and is a good option if you’re on a budget.

It’s not as complicated as it sounds and is a good option if you’re on a budget…

Although there are a lot of different formulas you can use, a common one includes 5 tablespoons of hydrated magnesium sulfate, 1 tablespoon of chelated trace elements, 2 teaspoons of potassium sulfate, and 1 teaspoon of potassium nitrate. 

You mix all of these ingredients 1 and a half cups of distilled water. Make sure you keep any unused formula in the refrigerator.

Fish Tank Inside a Dimly Lit Room
Fish Tank Inside a Dimly Lit Room

How to Dose Fertilizer for Aquarium Plants

It’s important to dose the correct amount of fertilizer for your tank. If you add too much, then it could harm your fish and have a negative impact on your plants. In contrast, using too little won’t supply your plants with enough nutrients.

It’s important to dose the correct amount of fertilizer for your tank. If you add too much, then it could harm your fish…

Most fertilizers will come with dosage instructions to help you figure out how much to use in your tank. Additionally, the type of fertilizer you’re using and whether you’re dosing CO2 will influence this.

If you were wondering, carbon dioxide (CO2) is very advantageous for growth. A lot of aquarists inject CO2 in their natural aquariums as it aids with photosynthesis. 

How to Apply Fertilizers?

Remember, tablets/capsules go underneath your substrate near the roots of your plants, while liquid fertilizer is added directly to your aquarium. Aquarium soil or substrate is put on the bottom of your aquarium.

There are a few different dosing methods when it comes to fertilizing your planted tank, which I’ve explained below. You can think of dosing as a diet plan for your tank. Every tank is different and each dosing routine has its own methodologies, advantages and aims. Let’s take a look at the most common ones now… 

EI Dosing

EI dosing (Estimative Index) works on the basis that when plants are given ample nutrients, they outcompete any algae in the aquarium. EI doses are meant to be high for this reason. 

Typical EI values per week is nitrate 20 ppm (parts per million), magnesium 10 ppm, phosphate 3 ppm, potassium 30 ppm, and iron 0.5 ppm.

TIP

This method is best for high-tech tanks with CO2 injection, powerful lighting, and a strong water flow.

ADA Dosing

ADA (Aqua Design Amano) liquid fertilizers are meant to be used in conjunction with ADA aquasoil, a nutrient-rich substrate. Very little liquid fertilizer is used as the soil is the main supplier of nutrients. 

Standard ADA values per week are; potassium 20 to 24 ppm, 1 to 6+ ppm nitrate, phosphate 1.4 to 4+ ppm, iron 0.03 to 0.06 ppm, and a very small quantity of magnesium.

TIP

As this method of dosing is quite lean, it’s best suited to tanks with low lighting and slow growing plants.

PPS-Pro Dosing

The PPS-Pro (Perpetual Preservation System) dosing approach is low-maintenance and quite easy to do. 

Depending on the amount of light in your aquarium, the recommended values each week for the PPS-Pro method are different. For example, average values for a tank with moderate lighting are potassium 9 ppm, nitrate 7ppm, phosphate 0.7 ppm, magnesium 0.35 ppm, and a small quantity of iron.

This approach works best for heavily planted aquariums with a moderate amount of fish waste. It’s designed for aquarists who want a low-maintenance fertilizing routine that doesn’t need much tweaking. 

TIP

The method is incredibly versatile as it works for all lighting conditions, all substrates, and all amounts of water changes.

PMDD Dosing

PMDD (Poor Man’s Dosing Drops) method aims to grow plants and reduce the amount of algae. It includes using a little too much light, CO2, nitrogen, potassium, and trace nutrients. This will keep algae to a minimum, so they don’t starve plants of nutrients.

Standard values for this method are nitrate 3 to 5 ppm, phosphate 0 to 1 ppm, and iron 0.1 ppm.

TIP

In planted tanks with a lot of algae, the PMDD approach can be very effective at keeping plants healthy and controlling algae.

Aquarium Plant Fertilizer Reviews

Now that you’ve got all the information you need to know about aquarium fertilizers, you’re probably looking for some top recommendations. In this section of the article, I’ve reviewed a variety of products to help you find the right fertilizer for you!

Best All-Rounder

API Root Tabs Freshwater Aquarium Plant Fertilizer

API tabs are an affordable but good-quality option for a natural aquarium. The tablets are slow-releasing, which means they don’t need to be replaced too frequently.

API Root Tabs Freshwater Aquarium Plant Fertilizer

API tabs are an affordable but good-quality option for a natural aquarium. The tablets are slow-releasing, which means they don’t need to be replaced too frequently.

The formula uses essential nutrients like carbon, iron, and potassium to help keep your aquatic greenery healthy. This promotes strong development and growth of roots.

These tabs only need to be added to your substrate once a month, making them a great low-maintenance choice. Some fertilizers need to be added to your tank every day, which isn’t ideal if you have a busy schedule. 

This plant fertilizer (aquarium food) is also easy to use as all you need to do is place the tablets underneath your substrate, near the roots of your plants. 

The main issue with these tablets is that they can turn your water cloudy and murky for a couple of days. While this doesn’t harm your fish or plants, it can look unsightly.

Specs

Pros

  • Easy to use and long-lasting
  • Provides a good range of nutrients
  • Affordable

Cons

  • Can turn your water cloudy when added

Best on a Budget

Osmocote Plus Aquarium Root Tabs

Osmocote Plus root tabs are extremely affordable and keep your aquarium nourished. They’re particularly beneficial for heavy root feeders like Amazon swords.

Osmocote Plus Aquarium Root Tabs

Osmocote Plus root tabs are extremely affordable and keep your aquarium nourished. They’re particularly beneficial for heavy root feeders like Amazon swords. 

The tablets contain 11 essential vitamins and minerals to get your aquatic greenery lush and colorful. The capsules are easy to use as you simply place them under your substrate and let them get to work.

Unfortunately, these capsules don’t always seem to work for some plants, which can result in disappointing growth. This might be because they lack some macronutrients or micronutrients that certain species require.

They also have a tendency to float. Tablets that come in capsule form seem to get this issue frequently, which is a bit frustrating.

Pros

  • Very affordable
  • Contains 11 types of minerals
  • Ideal for Amazon swords and similar species

Cons

  • Might not be suitable for some planted tanks
  • Capsules tend to float
  • Can turn water cloudy or murky

Editor’s Choice

NILOCG ThriveCaps Root Tabs

They are a blend of dry Thrive mix, iron rich clay, and mineralized top soil. This composition contains all the necessary vitamins and minerals you need to get your aquarium looking healthy.

NILOCG ThriveCaps Root Tabs

My personal favorite out of all the products I’ve looked at are the ThriveCaps capsules. They are a blend of dry Thrive mix, iron rich clay, and mineralized top soil. This composition contains all the necessary vitamins and minerals you need to get your aquarium looking healthy.

The tablets are incredibly easy to add to your fish tank as they simply go under your substrate, near the roots. The capsules work by slowly releasing vitamins and minerals over time. They make it easy to get a gorgeous natural aquarium.

You only need to replace the tablets every 3 or 4 months, so they’re very long-lasting. This also makes them ideal for aquarists with busy schedules. 

You can simply pop a few of these tablets into your aquarium and forget about them for the next few months. That’s very easy maintenance compared to some other fertilizers.

These plant fertilizer aquarium tablets come in capsule form, so they have a tendency to float if they are not buried deep into the substrate. 

Specs

Pros

  • Long-lasting
  • Easy maintenance
  • Contains a variety of vitamins/minerals

Cons

  • Capsules have a tendency to float

API Leaf Zone Plant Treatment

This aquarium plant food is a fantastic choice for aquarists on a budget. It contains essential nutrients like chelated iron and potassium, which promotes healthy leaves and strong roots.

API Leaf Zone Plant Treatment

This aquarium plant food is a fantastic choice for aquarists on a budget. It contains essential nutrients like chelated iron and potassium, which promotes healthy leaves and strong roots. This helps make sure your plants are free of decay and yellow/brown discoloration. 

The formula is designed to be rapidly absorbed by your plants, so it starts working very quickly. You only need to add it once a week, too, unlike some other fertilizers which require daily doses.

My main gripe with the formula of this product is that it doesn’t contain enough nutrients for some species. It seems to be adequate for less demanding plants, but not for more high-maintenance types.

Make sure you check the requirements of your aquatic plants to see if this product is right for you. The solution can also turn your water cloudy or murky temporarily. 

Specs

  • Type: Liquid
  • Item Weight: 1.2 lbs
  • Packaging Size: 1” x 1” x 6”

Pros

  • Good food source for most plants
  • Rapid absorption
  • Great value

Cons

  • Might be unsuitable for high-maintenance plants

Seachem Flourish Advance Growth Supplement

Seachem are well-known in the fishkeeping community for their high-quality products, and this one is no different. Seachem Flourish Advance contains minerals and phytohormones that keep your plants at peak health.

Seachem Flourish Advance Growth Supplement

Seachem are well-known in the fishkeeping community for their high-quality products, and this one is no different. Seachem Flourish Advance contains minerals and phytohormones that keep your plants at peak health.

The solution is quickly absorbed, so it starts working straight away. This also increases your plants’ resistance to disease and keeps them free of stress.

The formula usually takes around 10 to 14 days before you see any noticeable results. However, after this period, you should see significant growth in the stems and leaves of your plants. 

You need to dose this supplement daily for optimal effectiveness, so it’s not the most easy method, especially for aquarists with a busy routine. The solution can also cause a jelly-like film to develop on the walls of your aquarium or inside your filter.

It’s important to note that this product is a specialized additive and should be used with an aquarium fertilizer. On its own, it does not supply your aquatic greenery with enough nutrients to thrive. 

Specs

Pros

  • Provides plant roots and leaves with optimal growth
  • Rapid absorption
  • Can help prevent disease

Cons

  • Visible results can be slow and needs to be added daily
  • Can cause a jelly-like film to develop
  • Needs to be used with a fertilizer

Summary

Here’s a quick recap of all our top picks…

Best All-Rounder

Out of all the products I’ve reviewed, I think API Plant Tablets are the clear winner. They contain iron, potassium, carbon, and other minerals to get a stunning natural aquarium. 

I like that the tablets are relatively inexpensive and last a fairly long time. They only need to be replaced every month, which makes for easy maintenance. Some other aquatic plant food needs to be dosed daily, which can be a hassle if you have a busy schedule.

My only issue with the API plant tablets is that they can turn your water cloudy or murky. Although this doesn’t harm your aquatic life, it can make your aquarium look unsightly.

Best on a Budget

If you don’t think API plant tablets are a good match for your aquarium, then I also recommend Osmocote Plus Plant Tablets or ThriveCaps Aquarium Plant Tablets. The former is a fantastic option for aquarists on a budget due to their low price.

They contain 11 types of minerals and work especially well for heavy root feeders. However, they’re not a good match for some tanks with live greenery as they lack some macronutrients and micronutrients. In addition to this, the capsules have a tendency to float due to their high buoyancy. 

Editor’s Choice

ThriveCaps root tablets also suffer from floating, but they work well for a lot of planted aquariums as they contain a lot of minerals. The capsules last for 3 or months, so they are very long-lasting compared to some of the other products. 

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