Best Aquarium Substrate for Plants in 2021: Reviews with Comparisons

Best Aquarium Substrate for Plants in 2021: Reviews with Comparisons

Living plants are a fantastic way to decorate an aquarium and help contribute to a healthy underwater environment. They may even be an occasional snack for your fish, as well as providing relaxing hiding places and shady spots for exploration. However, creating an aquarium environment that is healthy and stable for plants and fish can be challenging. The right aquarium substrate for plants can make all the difference. Here are the best aquarium substrate for plants.

Best Aquarium Substrate for Plants: Reviews

Landen Aqua Soil Substrate for Natural Planted Aquarium

The Landen Aqua Soil Substrate for Natural Planted Aquarium is a natural substrate that helps build a healthy root system for fish tank plants. The porous surface provides a breeding ground for beneficial bacteria that keeps an aquarium stable.

It raises the pH of your water, creating the mildly acidic conditions preferred by shrimp and many aquatic plants. While it softens water, over time, it also releases healthy trace minerals and nutrients. These promote healthy fish and shrimp in an aquarium.

The Landen Aqua Soil Substrate does not require rinsing or layering and does not make your water cloudy. However, the substrate should always be given a week in a tank without fish while the filter runs to balance the nitrogen cycle and promote healthy bacteria.

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Seachem Flourite Black Clay Gravel

Flourite is one of the most popular substrates for living plants because it is durable and doesn’t break down over time. The Seachem Flourite Black Clay Gravel is a complete substrate formula that doesn’t require mixing or layering with other materials and is large enough for compatibility with underwater filters.

In addition, the porous surface benefits the growth of beneficial bacteria while it provides stable soil for living plants.

The Seachem Flourite Black Clay Gravel has no chemicals and does not alter the pH of a tank. However, it can become dusty and should be thoroughly rinsed before use, and water added carefully to prevent clouding.

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Ultum Nature Controsoil Freshwater Planted Aquarium Substrate

Ultum Nature Controsoil is created from the volcanic ash of Mount Aso in Japan. This substrate is black, with the texture and porosity needed for healthy plant roots and healthy aquatic bacteria. It softens and acidifies the water in a fish tank. It also naturally buffers the water and absorbs impurities, reducing ammonia and algae growth.

Ultum Nature Controsoil Freshwater Planted Aquarium Substrate does not require rinsing before use and won’t cloud the water.

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Mr. Aqua N-MAR-066 1 L Fine Pet Habitat Water Plant Soil

Mr. Aqua N-MAR-066 Fine Pet Habitat Water Plant Soil comprises a proprietary blend of organic and inert ingredients to provide the nutrients aquarium plants require. It buffers the pH in aquarium water from 6.6-6.8 and purifies and clarifies water that has been stained by driftwood. In addition, the porous structure promotes root growth and healthy soil bacteria in a fish tank while softening water.

This aquarium substrate is long-lasting and can go from 12-18 months before replacement. In addition, it does not require rinsing.

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Fluval Plant and Shrimp Stratum for Fish Tanks

Fluval Plant and Shrimp Stratum is made from volcanic soil that is high in minerals. It promotes neutral to mildly acidic pH in the water. It also stimulates strong plant growth and harboring healthy bacteria. In addition, it provides a full complement of macro and micronutrients that plants need.

This substrate does not discolor water and can help clarify water that has been discolored by natural driftwood. In addition, it is long-lasting and does not compact over time.

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Buyer’s Guide

Choosing an aquarium substrate that is healthy for your plants, fish, and water quality can be challenging. Here’s what you need to know about selecting the right substrate.

Substrate Size

For living plants, choose a substrate that is from 3-8mm in size. Large granules are difficult for roots to embed in, and small ones can crush the roots.

Substrate Material

In the old days, aquarists had to make their own substrates, blending soil and clay and vermiculite and other ingredients to create a suitable substrate for plants. Today, there is a vast range of pre-formulated substrates that are ready to use with no additions. All of our favorite products on this list are pre-formulated substrates.

Substrate Layering

While substrate layering isn’t strictly necessary, it’s often the best way to create the best environment for your plants and your fish. Adding a base layer of peat, clay, or fertilizer provides nutrients for the plants. Adding a 3-7mm plant substrate layer provides added nutrition and gives the plants a foundation for their roots to grow.

Topping it with a layer of sand or fine gravel (1-2mm) helps provide a finished surface that protects your water quality from the nutrients in the soil while giving fish a safe and healthy surface to burrow in. The top layer can also be aesthetic, providing you with the look you want in your aquarium.

Substrate Color

Substrates for living plants come in a few colors, ranging from black or grey to brown or tan. If you want a different substrate color for aesthetic reasons, add a layer of your chosen color over the plant substrate layer.

Substrate Durability

Everyone who maintains a container garden knows that over time, soil compacts down and loses its nutrients. Most fish tank living plant substrates eventually need to be replaced to promote plant health and growth. Look for a substrate that lasts a long time, with fewer replacements.

Substrates and Water Chemistry

A substrate for living aquarium plants will always affect your fish tank water. Here are some reasons why.

They are Made of Soil

Living plant substrates are made of some kind of soil (instead of sand or pebbles), so plants can root and grow in them. As you might expect, mixing soil and water typically creates some kind of mud or cloudiness.

They Have Plant Nutrients

Because living plant substrates also provide nutrients that plants require, they affect water chemistry. For example, almost all new living plant aquarium substrates will cause an ammonia spike in the first few days of being added to the tank. This is why you should never add a new substrate to a tank with fish living in it.

Soil nutrients can also affect the water’s pH and mineral composition, potentially softening or hardening water.

They Have a Porous Surface

The tiny surface irregularities in living plant substrates are beneficial for plant roots and healthy aquarium bacteria. After the substrate’s initial ammonia spike, it plays a vital role in maintaining your fish tank’s nitrogen cycle and in buffering your water quality from sudden changes.


Remember that you will need at least 3 inches of substrate for the plants for a planted tank and may want to layer a different substrate on top. Most bags of substrate will indicate on the label how many square inches of the aquarium that bag can fill.

Prices can add up quickly, depending on the size of your tank, and can vary dramatically from product to product. When comparing substrates, be mindful of how many bags you need to buy for your specific aquarium setup.

Consider Planting Living Plants Inside Aquarium-Safe Containers

Instead of covering your entire fish tank with a planting substrate, consider planting your aquarium plants inside cups or glasses and placing those inside your fish tank. This method allows you to use your expensive, nutrient-rich plant substrate precisely at the roots of your plant without needing to cover the entire bottom of your aquarium.

It also allows you to easily move or adjust your living plants without jeopardizing their delicate root systems or disrupting your substrate surface.


How Do You Add or Change Substrate in an Existing Fish Tank?

Most living plant aquarium substrates are designed to be used when setting up and initially cycling a tank and not added or used while fish live in the water. However, they can make the water cloudy for up to a day and cause an ammonia spike for several days, so it is usually recommended to allow the new substrate and plants to establish themselves in a fish-free tank for a week.

So how can you change substrate in an existing tank? Because each living plant substrate is different, it’s essential to follow the manufacturer’s recommendations, but here’s a general overview of the process:

  1. Remove half of the water from your established tank.
  2. Remove décor and plants and place them in a bucket.
  3. Extract more water from the tank.
  4. Remove fish from the tank and place them in a bucket or holding tank.
  5. Remove the rest of the water from the tank.
  6. Discard the old substrate from the tank.
  7. Lay down the new substrate planting layer.
  8. Place your living aquarium plants in the soil.
  9. Add surface gravel or a sand layer, if desired.
  10. If you have a sculpted surface with hills and valleys, lay a sheet of cling film over the substrate to preserve the shape.
  11. Place a shallow bowl in the bottom of your fish tank (on top of the cling film, if you are using it).
  12. Pour replacement water gently into the bowl, allowing it to spill over the sides and begin to fill the aquarium. This will enable you to fill the aquarium without disturbing the substrate.
  13. Fill the aquarium with water.
  14. Remove the bowl (and the cling film, if applicable).
  15. Replace tank décor.
  16. Allow the filter to run for an hour or so until the water is clear. Then, if necessary, use a water clarifier following the manufacturer’s instructions.
  17. Replace the fish in the tank.
  18. Test the water daily and perform large (50% or more) water changes daily until the ammonia spike has passed and your water chemistry is balanced.

After this initial process, consider adding liquid aquarium plant fertilizer after large water changes since large water changes can remove the nutrients provided by the substrate. Ensure that any fertilizer is safe for the fish in your tank, and read the label carefully.

Remember to never replace aquarium substrate and filter media at the same time to preserve your healthy bacteria. If you change or replace substrate, wait at least two weeks before cleaning or changing the filter.

What’s the Best Aquarium Substrate for Both Plants and Fish?

Very often, the best substrate for nourishing plants and establishing healthy roots is not the best substrate for fish. Especially if your fish are diggers or sifters. If you need to provide the right substrate for your fish and your living aquarium plants, the best solution is to layer your substrate.

First, use a soil substrate for plant roots and health. Then add a generous layer of a fish-friendly substrate over the top. Choose sand, coral, gravel, or whatever is best for your fish and for your style of fish tank.

Can You Siphon a Fish Tank Without Disturbing the Substrate?

Many people are accustomed to cleaning a fish tank by siphoning up the gravel and removing all the waste and debris. However, you should not disturb a planted substrate in this way. Also, aggressive siphoning may mix up your carefully layered substrates.

Instead, use a gentle siphon held over the surface of the substrate. Sucking up waste and debris without lifting and stirring the substrate below. This can take some practice to perfect, as you need to control the vacuum suction with one hand and the careful position of the siphon with the other.

To make it easier, try to minimize waste and debris in the tank by avoiding overfeeding your fish, and consider adding algae-eating species that will help keep the substrate clean for you.


The best aquarium substrate for the health and vitality of your aquatic plants is Mr. Aqua N-MAR-066 Water Plant Soil. It has organic and inert ingredients and is high in all the nutrients aquatic plants require. It also softens water, decreases pH, and helps to stabilize water quality, reducing water changes.

The granules are smooth, so they are better for bottom-loving fish but porous for excellent root structure and healthy bacteria. However, it is also one of the more expensive options, and it needs to be replaced every 12-18 months. It also isn’t offered in the range of sizes and colors as some other aquarium plant substrates.

For a more budget-friendly alternative, consider Seachem Flourite. Flourite is inert, with no chemicals, so it does not alter the pH of your water. However, it still has plenty of the healthy minerals plants need. It’s affordable and comes in a wide range of colors and sizes to fit many décor styles.

Because it’s an inert clay, it lasts a long time and can go years between changing. However, it is dusty and requires rinsing and preparation before use. In addition, it can have a rougher, sharper particle surface that isn’t as healthy for bottom-dwelling fish or plants with more delicate roots.

Finally, because it doesn’t have as many nutrients, it’s a good idea to consider using a liquid plant fertilizer from time to time.