Claydite for plants: why we need it and what to replace it with

There are no universal components for soil, but many people do not hesitate to fill the drainage hole of the pot with expanded clay when replanting the next plant. The artificially produced material is used in almost all agro-technical tasks and even in landscape design.

What is expanded clay?

It is a natural material made of clay or clay shale, fired in a kiln at 1200 ° C. Contrary to popular belief, there is no division into construction and flower expanded clay – it is one and the same material.

On sale you can find pellets large (2-4 cm in diameter), medium (1-2 cm) and small (0.5-1 cm) fraction, as well as keramzite sand (less than 0.5 cm). Smooth outside granules have a porous structure inside – they weigh little, do not interfere with air exchange and are able to accumulate and release moisture.

Claydite applications

Lower drainage

The material will protect the roots from stagnant moisture, absorb the excess and slowly release it to the outside environment. This has a particularly positive effect on moisture-loving plants that require frequent watering: the soil will not get sour, and in the intervals between the flow of moisture (without extreme intervals) the flower will not suffer from drought.

The recommended thickness of the bottom drainage of claydite – from 2 cm, depending on the depth of the pot.

Upper drainage

By storing water, the granules prevent it from quickly evaporating from the surface of the substrate. If there is no one to water the flowers for a short vacation, top drainage of expanded clay will help moisture stay in the ground longer. However, if you water regularly with plenty of water, it is better not to do this idea – the soil can become sour.

The salts in tap water often deposit on the surface of the substrate – alkalinization of the soil occurs. For this reason, it is recommended to periodically change the top layer of soil in indoor plants. However, when using expanded clay, the salts accumulate on the shell of the pellets – it is easier to replace them.

Another advantage is protection against overheating in hot weather. Breathable expanded clay heats up in the sun slower than the ground.

The recommended thickness of the upper drainage of expanded clay – at least 1 cm.

As part of the soil mixture

A fine fraction of expanded clay is often used as a loosener for heavy soils. It promotes better air exchange and increases hygroscopicity of the substrate, protecting the roots from rotting in case of excessive watering. Often manufacturers include expanded clay in the substrate for cacti and other succulents. In collectors such a decision is not accepted, but there is logic in it: expanded clay is covered with a hard ceramic shell – it will easily absorb a small excess of moisture, but give it back less actively.


When growing without substrate, the main task is to provide the optimal amount of nutrients to the root system. Claydite is used as a medium to conduct water and dissolved fertilizers to the roots. It does not rot, does not get moldy, and performs well in intermittent flooding systems, in systems with frequent watering cycles, and even with the pump on all the time. Properly prepared for use, expanded clay is chemically neutral to the ions of the nutrient solution and is suitable for reuse.


Granules and expanded clay sand are used as mulch to protect the soil from mold in humid weather and to retain moisture in hot weather.

Landscape design

Colored expanded clay is used to decorate paths and flowerbeds. The colors used in the production are safe for plants and do not affect the quality of the soil.

Air humidification

In winter, many houseplants suffer from dry air. If you don’t have a humidifier, you can improve the situation with expanded clay. Soak the granules for a few hours, fill wide flat containers with them, pour water in and place them on window sills. Pots with plants can be placed directly on a layer of expanded clay.

What to replace expanded clay?

For drainage you can take stones (pebbles, gravel, gravel), coconut fiber and foam plastic. They do not accumulate moisture, but also do not affect the pH of the soil. Chipped bricks and clay crocks, as well as claydite, have an alkaline reaction, which should be taken into account when making up a soil mixture to the needs of a particular plant. Sometimes pine bark is used, but it is less durable. If the task is to prevent rapid evaporation of moisture, sphagnum moss can be used as upper drainage.

As a substrate loosener coarse sand, coconut fiber or Styrofoam crumbs are suitable. If you need a material with moisture-retaining capacity, pay attention to perlite and vermiculite – they have greater moisture capacity than claydite and have a pH close to neutral.

Disadvantages of expanded clay

  • Alkaline reaction. It is advisable to wash the granules before use. If expanded clay will be used for hydroponics, it is highly recommended to equalize its pH balance to 5-6 by soaking it in acidified electrolyte water. For indoor floriculture and horticulture this is not necessary, but desirable.
  • Claystone absorbs water more easily than it releases it to the outside environment. If you water too sparingly, moisture-loving plants will suffer more from drought.
  • The material does not rot or get moldy, but it is also not a favorable environment for beneficial microorganisms. To correct this deficiency, you can add a little coconut fiber (about 10% of the volume of expanded clay).
  • After about 3-4 years of operation pellets deteriorate – they need to be replaced by new ones.