How Fast Does Java Fern Grow (& 5 Ways To Speed It Up)

Last Updated on 2023-05-24

Are you thinking of including a java fern in your aquarium and wondering, “how fast does a java fern grow?” Sometimes, you want plants that will fill the space up quickly, providing cover for any fish and making it look green and beautiful within a few weeks. In these cases, you need to choose the right plant.

A java fern is a reasonably quick-growing option, but it isn’t the fastest, so you’ll have to decide whether it is suitable for your setup or whether a faster-growing plant would be better. In some cases, a java fern will be perfect.

How Fast Does Java Fern Grow?

Most java ferns can be purchased when they are around 3 to 5 inches high, according to EverythingFishKeeping, and they can grow around 1 inch per month if they are kept in the proper conditions. A java fern with good lighting, the right temperature, and the right level of nutrients should grow about 12 inches in a year.

Java ferns only get to around 13 inches tall, so most will reach their full height within a year or 2. That makes them great for medium-sized aquariums, and they will look lovely fanning out in the water, with their emerald green leaves flowing with the current.

However, if you need a plant that will fill space very quickly, you might be better off choosing an Amazon Sword or some Hornwort, as these grow much more quickly and will fill the space.

Is Java Fern Slow Growing?

Java ferns can grow very slowly if the conditions are not suitable for them – and sometimes, a plant will not grow at all. The commonest cause of problems is the planting conditions, as many people bury their java fern’s roots in the substrate.

Unfortunately, this prevents the plant from taking up nutrients effectively, leading to slow growth.

According to Aquariadise, a java fern needs to be anchored to a rock or some driftwood instead.

If you have buried your java fern, you’ll want to correct this as soon as possible to help the plant grow quickly.

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Why Is My Java Fern Not Growing Fast?

If your java fern seems to be growing very slowly, check the below suggestions to see what might be wrong.

Being Buried In The Substrate

As mentioned above, java ferns will not thrive if their roots are buried in the substrate – and many people make this mistake. It makes sense because most plants like to be buried, but java ferns prefer to be free-floating, and they will be happiest attached to a rock. If they are buried in the sand, their roots will not get access to enough oxygen and nutrients.

Not Enough Food

Java ferns also need sufficient nutrition; they absorb this from the water rather than from the substrate. If your water is low in nutrients and the plant can’t get enough food to produce new growth, it will hardly grow at all.

Not Enough Light

If your java plant isn’t getting enough light, it also won’t be able to photosynthesize and grow – which will slow it down significantly. However, too much light can also contribute to problems, so you need to balance this carefully.

Algal Growth

Algae will compete with your java fern for light, nutrients, and space if you let it build up in your tank, and once algae have got going, it can be hard to stop them. Algae will take over and damage many of your plants, not just your java fern, if you let them get a foothold in your tank.

Being Overcrowded

If you have a lot of other plants in your aquarium, they may take up the space, light, and nutrients your java fern needs, especially if they grow very close to it. Having a lot of foliage can be a good thing, but you need to make sure your java fern has space to grow into, or it can’t produce new leaves.

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How To Grow Java Fern Fast

If you want to make sure your java fern grows quickly, try some of the following suggestions.

Feed The Fern

As mentioned above, having access to the right nutrients is critical for a java fern, so you should make sure that you feed it regularly with a liquid fertilizer. It’s also a good idea to check the water quality and make sure the fern isn’t suffering from any deficiencies. Shuncy points out that a nitrogen deficiency may stunt the plant’s growth.

Increase The Light Levels

A normal bulb is fine for your java fern, but if the bulb is too dim and the plant isn’t getting much light, it won’t grow well. Make sure you aren’t turning the aquarium lights off too early in the day. AquariumTidings recommends using incandescent bulbs for at least 6 hours of light per day.

Remove Algae From The Tank

If your tank is getting a lot of algae in it, you will need to tackle this before it starts having a negative effect on your java fern – as it will block out the plant’s light, as well as compete with it for nutrients.

You should be able to decrease the algae by cleaning the tank regularly and making sure that you only add as much food as is needed in terms of both your plants and your fish stock. You can add cleaner fish or reduce the level of nutrients in the water if you’re having problems. Don’t let algae take over if you want your java fern to flourish.

Make Sure The Roots Are Free

If you have buried your java fern in the substrate, move it immediately, as none of the other fixes will help if its roots are still buried. It may even begin to rot because it won’t get enough oxygen flowing around the roots. Allow the java fern to float freely until it attaches itself to a rock or piece of driftwood, or use some suitable glue to attach it to your desired spot.

Don’t Remove The Plantlets

Many java ferns start producing plantlets on their leaves once they are established, and when you take these off, your plant will put energy into making new babies. If you don’t remove these shoots but instead allow them to stay on the plant, you will help it to conserve energy rather than encouraging it to produce more new shoots.

This should encourage it to put more energy and nutrients into its own growth rather than that of its babies, which should help.


Java ferns are quite fast-growing plants and make wonderful additions to most aquariums, but they won’t fill a space in a matter of weeks. You will need to be reasonably patient and make sure you are providing the best possible conditions for them. Java ferns aren’t fussy plants, but they do need the right degree of light and nutrients if they are to grow well.

If your java fern seems sick or is growing very slowly, do a water test to check whether it is suffering from a nutrient deficiency, and then correct the water conditions if necessary. Leave any offspring attached so that the plant doesn’t immediately produce more, and your java fern should reach its full height within about a year or two.

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