Planted aquarium with swimming fish.

Aquarium Plants in Gravel: Pros, Cons, Tips, and Species

Gravel is an obvious and popular choice for fish tanks. This inert substrate comes in various shapes, colors, and sizes, and it is pretty and affordable.

But is it suitable for all kinds of tanks?

Can you plant aquatic plants in gravel and expect them to grow?

Gravel is an excellent choice for root-feeding water plants. It anchors them well and leaves enough room for the root systems to develop. It lacks natural nutrients, but mixing it up with aqua soil or root tablets helps plants develop more quickly.

Indeed, gravel is inert, meaning that it doesn’t provide nutrients to plants by itself, but in a living, breathing aquarium this will change rather quickly.

And while most plant species will feel well in gravel, there are a few that absolutely love it. I selected five plants that can help you set up a colorful tank with minimum fuss, as they are pretty, fast-growing, and sturdy:

  • Amazon Sword plant
  • Vallisneria 
  • Saggittaria Subulata
  • Ludwigia Repens
  • Red Tiger Lotus

These five are excellent starter plants that thrive in gravel. More on that in a bit.

Before that, let’s break down the advantages and disadvantages gravel brings to your fish tank.

Pros of Gravel Substrate

Gravel is a popular choice for many reasons. It:

  • Looks great
  • Comes in many colors and sizes
  • Is very affordable
  • Is excellent for root feeders
  • Is easy to vacuum
  • Provides natural filtration

Beauty is in the eye of the beholder, but gravel usually makes for excellent aquascapes and fish tank setups. White, brown, yellow, black, electric shades, round, or more elongated, the choices are numerous and each has its charm.

What’s more, gravel is one of the most affordable substrates out there. Ideally, you should buy it at the local fish shop but a stone quarry or a hardware store might also have what you need. It will likely be cheaper but also considerably dirtier, so there’s this tradeoff.

Another thing about gravel is that it is very easy to vacuum during regular tank maintenance. Unlike sand and other finer and lighter materials, it won’t clog the siphon.

And since we are discussing whether gravel is good for plants, you’ll have to cover the bottom of the tank with about 3 inches (10cm) of gravel. Such a thick substrate layer will act as a natural biofilter. Thanks to the bacteria that will thrive in it, the gravel substrate will absorb waste and maintain water balance.

The gravel’s natural looseness allows for good aeration and water flow, especially when cleaned regularly.

Cons of Gravel Substrate

The pros far outweigh the cons, but here are a couple of considerations when it comes to gravel:

  • It is inert
  • Can accumulate a lot of dirt
  • Color is likely to fade
  • Not ideal for all fish species

Gravel in a new tank will lack nutrients. The root-feeding plants develop extensive root systems to reach more food. You can help their efforts by adding a bit of aqua soil or root tablets.

Further down the line, in a tank with fish, fertilizers become less of a need, as gravel makes for an excellent biofilter. I am not talking about under-substrate filters here. See, its relative looseness allows for roots to spread. But it also absorbs detritus and waste to become a decent breeding ground for aquatic plants.

Conversely, if you don’t have enough plants and don’t vacuum the gravel regularly, it can become messy and dirty-looking fast. Even with proper maintenance, if the gravel coloration is bright and unnatural, it will likely fade over time.

Lastly, certain species like kuhli loaches and corydoras are much happier with sand than gravel. The kuhlis prefer finer substrate to occasionally bury under, while corydoras sift sand through their gills. Also, even the most rounded gravel will likely damage their barbels.

What Gravel to Choose

I won’t advise you on the exact color, as that’s entirely up to you. You may go for a very natural brownish hue or something more artificial and visually stunning.

I used to be a stickler for the natural-looking setups but my latest tank is with electric-blue quartz sand, so there’s that. My little daughter loves it. Let personal taste and the other decorations you might already have dictate the gravel color.

All the same, you should know that darker substrates tend to make fish color stand out and, potentially, improve fish health.

What you should stick to is round or elongated gravel but not a sharp one. The occasional sharp pebble isn’t the end of the world, but if the majority of the gravel is sharp and edgy it will damage your fish.

If you are having only a planted tank or a betta tank, then it doesn’t really matter.

What matters, though, is the size. Select gravel that is between 3-9 millimeters. Larger than that and it becomes more unwieldy, making it harder to do a fine aquascaping.

Gravel finer than 3mm is approaching the size of coarse sand already. Sand is a great substrate in its own right, but it isn’t always the best for live plants. Fish can uproot plants buried in sand, especially if it is a fine, light variety.

As I mentioned, you can find pretty gravel in hardware stores and stone quarries. As long as they are without sharp edges, the stones will do for a fish tank.

Now, regardless of whether you buy your gravel from the hardware store or, the better option, the local fish store, wash it thoroughly. Sift and running cold water are the best tools for this purpose. Washing gravel for a large tank may sound like a tedious task, but it is a one-time job. If done properly.

5 Aquarium Plants that Thrive in Gravel

Here are five plants that love gravel and will thrive in it. The first three plants on the list are fast growers that are ideal for starting tanks. Early on, you should focus on fast-growing plants for two reasons:

  1. Save money — A few fast growers will make for a lush aquarium much sooner than species like Anubias or cryptocorynes.
  2. Suppress algae growth —- Fast-growing water plants will compete more efficiently with algae for nutrients. A starting tank is likely to be susceptible to various types of algae.

What’s more, these three plants, Amazon Sword, Vallisneria, and Saggitaria make for good contrast and balance. The Amazons have magnificent leaves and are excellent for a backdrop-centerpiece. The Vallisneria can make a dense forest on its own in one of the corners of the tank.

And the Saggittaria is small enough to cover the front and medium parts of the tank.

Besides their shared love for gravel, these three species like moderate light. If your light is stronger, consider placing the Saggittaria under the sprawling Vallisneria leaves.

Add a bit of moss and you have a good starting point.

The last two entries on the list have red leaves that add variety and color to the tank. The Ludwigia is fairly straightforward to grow, but the Red Tiger Lotus might need more space or fertilization.

1. Amazon Sword Plant

Light: Moderate to strong

pH: 6.5-7.5

Temperature: 24-28 C

Growth speed: Medium to quick

Placement: Back, center

That’s one of my favorite plants. It is sturdy, fast-growing, and visually impressive. It is rather large and makes for a perfect backdrop plant.

It develops a large, powerful root system. The looseness of the gravel is perfect for it to establish a steady foothold and grow to its maximum potential.

Keep in mind that Amazons sometimes become yellow and wilt soon after being planted. That’s not unusual, as they need some time to get used to the new environment. Trim the yellow leaves and their stems.

As long as the water conditions are good, the plant will recover and start producing a healthy green mass.

It is ideal for beginners as it develops relatively quickly even without extra fertilization.

2. Vallisneria

Light: Moderate to strong

pH: 6.5-7.5

Temperature: 22-28 C

Growth speed: Quick

Placement: Back, side

The Vallisneria species are long, leafy plants that develop strong roots. The most popular varieties are giant and dwarf Vallisneria, with the former reaching up to 60cm in length. The dwarf variety grows up to 25cm.

Lush Giant Vallisneria
Giant Vallisneria quickly creates lush, dense patches of green.

It is a fast-growing plant that requires little care. It is adaptable to different water parameters and makes for dense vegetation. That’s why it’s necessary to trim it every now and again.

The Vallisneria plants propagate through off-shooting whiskers. They crawl through sand or gravel and soon end up as a new plant.

3. Saggittaria Subulata

Light: Moderate

pH: 6.0-8.0

Temperature: 20-28 C

Growth speed: Quick

Placement: Front, middle

Dwarf Saggittaria is a very quick-growing plant. It is vibrant, bottom dwellers love it, and it makes for a fine counterpoint to the Vallisneria or the Ludwigia Repens.

Saggittaria establishes fairly quickly and can outcompete algae for nutrients very well.

One thing to consider is the light intensity. It prefers moderate lighting and while it can tolerate slightly stronger illumination, it may start melting away if it is too bright for too long. Consider placing it under the shade that your Vallisneria may provide if the light is too strong.

If you go with medium light, you might very well add…

4. Ludwigia Repens

Light: Low to moderate

pH: 6.0-8.0

Temperature: 20-28 C

Growth speed: Quick

Placement: Front, middle

Ludwigia is a pretty, reddish plant that looks nothing like the other entries on the list. Its strong stem has relatively small leaves. It creates excellent underwater forests because its straight stalks resemble trees a bit.

It also prefers moderate lighting.

Ludwigia grows taller than the Saggittaria, adding another plane for swimming and hiding in the tank.

5. Red Tiger Lotus

Light: Moderate to strong

pH: 6.0-8.0

Temperature: 22-28 C

Growth speed: Quick

Placement: Front, middle

Red Tiger Lotus is probably my favorite red-leaf water plant. Its round leaves are beautiful and grow in all sizes. It often produces a single leaf with an extra-long stem that is shooting for the surface.

There are two things to consider when getting Red Tigers, though. They have a powerful root system starting from a ball. Don’t bury that ball in the gravel or sand, as it will rot and your plant will die. However, make sure to bury the roots well so the plant can establish itself in the gravel.

The other issue a Red Tiger Lotus may present is its high nutrient demands. I made the mistake to plant it next to my Ludiwiga forest and soon the Lotus outgrew them and suffocated them.

Now, that doesn’t mean that the Red Tiger Lotus needs fertilization. It can thrive without extra stimulation and will outcompete the algae in its vicinity.

The Red Lotus plants have other peculiarities too, but getting to know that colorful, awesome plant is well worth the effort.

How to Plant Plants in Gravel

Planting plants in gravel is a fairly straightforward process. But let’s lay some founding principles first.

1. The Gravel Thickness

Any substrate that will house root-feeding plants needs to be at least two inches or six centimeters. Better yet, add another inch or three centimeters.

Gravel is no exception to this rule. Three inches of gravel will provide ample room for the roots to grow. What’s more, it will quickly become the biodome of many helpful bacteria that will help with water chemistry.

Naturally, you can make the substrate layer thicker in certain parts of the tank and thinner in others. For instance, the Saggittaria Subulata and Ludwigia Repens have considerably smaller root systems than the Amazon Sword plants.

So, the minimal gravel thickness you should aim for is two inches, but it better be three for larger plants.

2. Tank Setup Order — to Fertilize or Not?

When setting up a new fish tank, first wash the gravel very carefully. Using a sift and running water is the fastest way, but you can soak it in a bucket and rinse it thoroughly. Even gravel from the fish shop should be washed carefully to avoid misty water.

Once clean, lay the gravel carefully. Don’t dump it all at once to avoid cracks in the fish tank. After all, we are talking about a bunch of small stones on a glass or acrylic bottom.

Before you add the decorations you want to use, be that driftwood, large stones, or something more thematic, consider adding aqua soil or root tablets. Added sparingly, they won’t break the bank and will help plants establish. However, the species I listed here can do well without any additional fertilization in a fish tank.

If it is your first planting, add water until the middle of the tank to see how your plants look once planted. If you feel confident, pour only enough water to cover the gravel and then start planting.

With less water, it is easier to plant.

3. Planting and Plant Arrangement

The principles for planting a new tank dictate putting the smaller plants in the front and middle ground, while the larger species should go to the background and the sides. If you can observe your tank from three sides, then keep the large water plants at the back.

You can use tweezers or your hands to bury the roots under the gravel.

Is Gravel Good for Plants?

Gravel is a top choice for fish and planted tanks. It looks great, supports large plants well, is easy to clean, and doesn’t cost a fortune.

Yes, it is inert, but you can always add a bit of aqua soil, root tablets, or liquid fertilizer to give your plants an early boost. Gravel is a very welcoming environment for a bacterial biodome, which will help your plants grow too.

Even without fertilizers, if the tank has fish, their waste will soon become a source of nutrition for your plants. You can plant all the plants you like in gravel.

With a little care, they will thrive.


Is sand or gravel better for a planted aquarium?

Plants do very well in both gravel and sand. The only caveat here is very fine sand, which may make it easy for plants to uproot. Gravel also retains debris better, delivering more nutrients without the help of additional fertilizers

Can I mix aqua soil with gravel?

You can mix aqua soil with gravel. That’s the optimal way to set up a beautiful tank with a nutrient-rich environment without spending a fortune. Choose in advance the places for plants and make pockets of aqua soil there. Cover it with gravel and then place the new plants. They’ll love it.

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