When to put plants in an aquarium?

In a new aquarium, plant the plants on the day of assembly, once the soil and decor are in place, with only a few centimeters of water. Then fill it slowly. You don't have to wait for the biological cycle: it's the fish that wait, not the plants. In an established aquarium, take advantage of a water change, when the level is lower.

In a new aquarium

The right time is between the decor and the filling. Earlier, the dry soil does not hold the plants. Later, the water obstructs the view and the nutrient soil lifts with every movement.

Tropica recommends planting when there are only a few centimeters of water. Fill slowly by pouring over a saucer, up to about 2 cm above the gravel, and spray the plants during the work so they stay moist. On nutrient soil, Fishipedia stays even lower, from a few millimeters to 1 cm above the soil.

Choose the soil before buying the plants: it is what decides what will be able to take root. Our article on the choice of substrate compares the options. Then place the plants from the back to the front if the hand must pass over, or start with low plants as Fishipedia recommends, as long as there is still room for the tweezers.

Before or after the biological cycle

The question comes up often: should you wait for the aquarium to be ready? For plants, no. They do not need a mature filter to settle in. Fishipedia even reminds that a good quantity of plants from the start helps consume the nutrients released by the soil, and to limit the startup algae.

However, they do not replace the cycle. The filter bacteria need time to settle in, and only nitrite measurements will tell you when to introduce the fish. Our freshwater aquarium guide describes this step.

Waiting to plant even presents a disadvantage. A lit tank without plants leaves the field open to algae, and planting later in a full aquarium is less comfortable. If you cannot plant on the day of assembly, keep the light off until the plants arrive.

In an established aquarium

To add a plant to an already inhabited aquarium, the best time is the weekly water change, of 20 to 25%. The level is lower, you already have your hand in the tank, and the lifted particles leave with the water.

1. Siphon and lower the level, as for a normal maintenance. Respect the instructions of the filter and heater manual.
2. Prepare the plant next to the aquarium, before dipping your hand.
3. Plant with tweezers, by spreading the soil without scratching it.
4. Complete slowly, with water at the same temperature.

The day you receive the plants

The best time remains as close as possible to the reception. A waiting plant weakens, especially if it dries out or gets cold. Open the package as soon as it arrives and leave the plants moist, as explained in our article on reception and acclimatization.

Rinse the plants under the tap and remove as much rock wool as possible, as Tropica asks. If you keep shrimp, be more careful: The Shrimp Farm reminds that potted plants can carry traces of pesticides, and intruders. A prior isolation can then be justified. Plants grown in a sterile environment, like in vitro, generally pose fewer problems.

The technique according to the plant

The timing is the same for all, but the technique changes. Here are the Tropica guidelines.

• Stem plants: remove the bottom leaves and plant the stems one by one, in a group.
• Rosette plants: separate the rosettes and remove the oldest leaves.
• Rhizome plants: do not bury them. Tie them or slide them between stones.
• Carpet plants: divide the clump into 4 to 10 portions, spread over the area.
• Floating plants: place them on the surface, keeping in mind that they cast shade on the rest of the tank.

For your first plants, keep it simple: our selection of easy plants will save you a lot of trials.

Frequently Asked Questions

Should you wait for the cycle to put the plants?

No. The plants can be installed before the cycle, right from the assembly. It's the fish that wait. Let the nitrites drop, with tests to back it up, before introducing them.

Can you plant in a full aquarium?

Yes, with a long tweezer, especially for a few plants. But it is simpler to lower the level during a water change. You see better, and the soil lifts less.

Do plants replace the biological cycle?

No. They help a little at the start, but the filter needs time for its bacteria to settle in. Test the nitrites before adding fish.

How to keep plants before planting them?

Leave them moist and in the light, in a little water, without leaving them in the cold or in direct sunlight. Plant them as soon as possible. Tropica recommends spraying the plants during the work to prevent them from drying out.

Should you cut the roots before planting?

Tropica recommends removing the pot and the rock wool, and shortening the roots that are too long to about 4 cm. Do not touch the rhizome of plants like Anubias, which must not be buried.

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Last updated: November 4, 2026.