Clay Pellets vs Rockwool

Rockwool and Clay pellets are two types of soil substitutes that both have benefits and downfalls. In this blog post I will be explaining how to use each, and a few reasons you may choose to use one over the other. 

Cost Rockwool is known to have a relatively low cost, but in more recent years prices have skyrocketed. Rockwool is not a reusable product, so it will have to be repurchased to keep growing.

Clay Pellets are a low cost option for a soil substitute. The cost has remained relatively stable over the years. This is a reusable product, meaning you only need to purchase it once and can reuse it over and over.

Maintenance Rockwool does not require any cleaning. Once a grow cycle is complete, rockwool can be composted. 

Clay Pellets must be washed between cycles to ensure the best possible outcome. Pellets must be washed in hot water to disinfect them.

Planting Consistant germination rate.

Consistant germination rate.

Algae Alage can often build up on the top layer of rockwool. We suggest replacing those sections with some new presoaked peices. No significant algae problems.


Both clay pellets and rockwool can be used as a growing medium in hydroponics. However, clay pellets are often considered to be a better choice for several reasons.

Firstly, clay pellets are much lighter than rockwool, which makes them easier to handle and transport. This can be particularly important in larger hydroponic setups, where the weight of the growing medium can become a significant factor.

Secondly, clay pellets provide excellent drainage and aeration to the roots of plants. They do not retain water as much as rockwool, which can be beneficial in preventing root rot and other moisture-related issues. Additionally, the porous nature of clay pellets allows air to circulate more freely around the roots, which can improve overall plant health and growth.

Thirdly, clay pellets are a more sustainable option compared to rockwool. Rockwool is made from a non-renewable resource (volcanic rock), while clay pellets are made from natural clay, which is widely available and can be easily sourced.

Overall, while both clay pellets and rockwool can be effective growing mediums for hydroponics, clay pellets are often preferred for their lightness, excellent drainage and aeration properties, and sustainability.