A plant filter as a natural water purifier for your pond. Do you want to make a plant filter for your pond but don't know what types of plant filters exist, such as a swamp filter also called a helophyte filter, and do you also want to know how to make one? Read all about plant filters and we also give you tips on which plants are best to use in a plant filter.

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All about plant filters

• What is a plant filter?
• What is the difference between a plant filter and a helophyte filter?
• How do you make a plant filter?
• What substrate in plant filter?
• What aquatic plants can go in a plant filter?

What is a plant filter?

A plant filter is a biological filter used to purify water by using different types of aquatic plants. It works by passing water through pond substrate in which pond plants grow that absorb and break down nutrients and contaminants from the pond water. A plant filter is installed in a pond where the plants are shielded from the rest of the pond by a constructed stone wall. Plant filters can be used in many different types of ponds people with koi ponds koi ponds often choose a plant filter because koi carp are known to often demolish aquatic plants.

What is the difference between a plant filter and a helophyte filter?

Helophyte filter 

A helophyte filter, also known as a swamp filter, is a natural filtration solution for ponds. The filter is made up of aquatic plants and its purpose is to remove waste products from the water so that the water values remain stable and pond animals and fish remain healthy. Because the helophyte filter uses only natural materials, such as aquatic plants, it is considered an environmentally friendly form of water treatment. Unlike other pond filters or pond pumps, the helophyte filter is therefore not harmful or damaging to the environment.

Plant filter

A plant filter pond is a type of pond filter that uses pond plants to purify the water. It is a screened area of the pond where aquatic plants such as reeds, water lilies and bulrush are planted. These plants have the ability to absorb harmful substances such as nitrite and ammonia from the water and convert them into nutrients for the plants. This naturally purifies the water.

So, the difference between a helophyte filter and a plant filter is that a helophyte filter is made in the middle of the pond water and a plant filter is made in a screened area of the pond.

How do you make a plant filter?

Following are the basic steps to create a screened plant filter in the pond:

1. Choose a suitable location

Choose a suitable location in the pond for your screened plant filter. Place the container at the bottom of the pond, allowing the holes in the bottom and sides of the container to allow water to flow.

2. Fill the restricted area

Fill the screened area with filter media such as pond substrate. This helps to support the plants and provides a place for beneficial pond bacteria to grow.

3. Place the plants in the screened area

Place the plants in the screened area and make sure that the roots of the plants are well tucked into the filter media.

Tip from pond specialist Simon:

Use loose plant filter plants to easily and cleanly plant a plant filter

4. Shielding plant filter

Make sure that the container with plant filter is fully screened so that no pond fish or other pond animals can get into it.

5. Add water

Run the water through the plant filter. The plants will purify the water by absorbing harmful substances such as nitrite and ammonia and converting them into nutrients for the plants.

6. Pond filter maintenance 

Check the water and plants in the filter regularly and perform maintenance, such as trimming aquatic plants, as needed.

What aquatic plants can go in a plant filter?

There are several types of plant filter plants that are suitable for a helophyte filter. When choosing plants, it is important to choose hardy specimens that can withstand various weather conditions. As a pond specialist, I recommend a number of strong aquatic plants suitable for a helophyte filter, including the Iris (Lis). This plant is known for its powerful purifying effect and helps keep water parameters stable. Also the Lischodder (Typha) is a suitable aquatic plant that is well able to purify the water in the pond.

What substrate in plant filter?

To create a healthy and balanced plant filter, it is recommended to put a porous pond substrate on the bottom. The pores of the stone granules allow pond bacteria to settle that help break down silt and keep the water clear. In addition, the substrate provides a good base for plants to take root and grow healthily, whether placed in a basket or with a plug. Read more about the benefits of pond substrate For a healthy pond environment.

Frequently asked questions about plant filters