Pioneering Hydroponics

Since 1976

Hydroponic Growing Media: Clay Pebbles

Clay pebbles have the perfect shape and surface to allow your plants’ roots to adhere to them and for beneficial bacteria to colonise. Additionally, clay pebbles have a porous structure with a high-water capacity, which releases both water and nutrients as plants require them.

The majority of plant seeds need three main factors from growing media, such as:

  • Good level of aeration, so that oxygen is readily available.

  • Consistent level of moisture.

  • Lack of pests and diseases.

How do Clay Pebbles Work?

Clay pebbles are made in a rotating kiln, in which clay is heated to between 1100℃ and 1200℃. The clay expands and remains highly porous with a rough finish, trapping air, retaining moisture, and oxygenating the nutrient solution.

Plant growth is sped up due to the great aeration level in the root zone. Clay pebbles also provide an excellent support structure for plants, adding much-needed stability. This grow media is very commonly used by itself in recirculating hydroponic systems, such as ebb and flood and drip irrigation.

They are also, however, used often for their properties in combination with coco and soil in potting, as a base layer and as a top layer. As a base layer, it increases drainage and as a top layer, it reduces evaporation caused by grow lights.

Benefits of Clay Pebbles in Hydroponics

  • Reusable. After each use, the clay pebbles can be thoroughly cleaned to remove any organic matter and salt build up before reusing. Unless you notice an extreme salt build up that will harm your plants, the pebbles can be used many times.

  • Fewer blockages. The high pore space allows for better percolation, which means that it’s rarely blocked or clogged. As such, ebb and flood systems benefit from this medium.

  • Roots stay oxygenated. Although not as great as perlite in air-holding capacity, clay pebbles have a good ability to hold air bubbles. In addition, they have a good percolation level, which reduces the possibility of problematic anaerobic areas to form.

  • Great for microbial colonisation. Clay pebbles are smooth but still allow for the colonisation of beneficial microbes. These microbes make essential nutrients available to your plants so that they can grow healthy and strong, and so that the hydroponic system is more stable.

How to use clay pebbles in hydroponics:

  1. Remove dirt and debris in excess from expanded clay pebbles by rinsing them.

  2. Fill your hydroponic pots or other containers with clay pebbles.

  3. Sprinkle plant seeds over the clay pebbles or transplant your seedlings - new transplants, however, are typically started in rockwool.

  4. Make sure to fill the hydroponic system’s reservoir with the nutrient solution according to specification. The solution should be changed every two weeks.

  5. Set the timer so that the plants’ container is flooded a couple of times a day, adjusting the frequency if you’re using a combination of clay pebbles and other growing medium.

  6. Check that water drains before it reaches the upper surface of the clay pebbles. This often encourages algae to grow, harming plant growth.

Contact us on 01695 554 080 or 01226 320 850 to know more about our hydroponic systems and other products. You can also become a stockist by getting in touch with us. We’re always happy to answer any query you might have.