Hydroponics with clay pellets

Source: Own work

Hydroponics with clay pellets

Passive hydroponics is the easiest method for the home gardener.

It combines all the advantages of hydroponics with ease of installation and maintenance.

It is the perfect solution for those who are never sure when to water or fertilize.

Materials needed:


Any waterproof pot that does not let the light in, will do. The pot has to consist of an inert material: plastic, ceramic… but no metals that will react with the nutrient solution.


The basket is an internal pot in which the plant is placed. It allows you to easily remove the plant from the pot to replant it in a larger pot or to rinse the outer pot and clay pellets.

It is also useful in tanks where different plants are grown together.

This is optional: if you grow only one plant in one outer pot, the basket is not essential.


The substrate must be inert, that is to say not reacting chemically with the nutrient solution.

It must also be capable of carrying the nutrient solution to the roots by capillary action.

The substrate generally used are expanded granules, which also provide mechanical support to the plant.


A gauge is necessary to check the level of the nutrient solution. It allows you to see when you need to water again.

Nutrient solution:

It is composed of water to which a specialized fertilizer for hydroponics is added.

Do not use fertilizer for plants grown in soil: they generally do not contain all the elements a plant needs, like micro-nutrients, i.e. that are present in minute quantities.


For the purpose of this article, I assumed that the plant is already accustomed to hydroponics.

If you want to transfer a plant from soil to hydroponics, see the following article: How to transfer to hydroponics.


  • Place the gauge at the bottom of the pot
  • Put a layer of clay granules in the bottom of pot
  • Place the plant on top of this layer
  • Fill the pot with clay granules up to 1-2 cm from the edge
  • Add to the nutrient solution (1/3 of the height of the pot or optional level on commercial gauges)


Passive hydroponic plants require little maintenance. Just check the gauge regularly and add the nutrient solution when the level is at the minimum.

It is recommended to rinse the  inside of the pot and clay granules with clear water once every 3-6 months to remove the crystals formed by the salts.