Clay Pebbles

Last Updated: January 23, 2017

Definition - What does Clay Pebbles mean?

Clay pebbles are a growing medium that is most often used in hydroponic gardening. In this type of gardening, soil is replaced by nutrient-rich water, but the plants may still need a stabilizing medium for their root structures to grow. Clay pebbles are also sometimes used in container gardens.

Because they have a neutral pH, clay pebbles provide a growing medium that is ideal for a wide variety of plants, and they are reusable as well. While clay pebbles do not offer their own nutrients to plants, they do provide a medium in which nutrients and water can easily be added for healthy growing cycles.

Clay pebbles are also known as expanded clay pebbles or hydroton.

MaximumYield explains Clay Pebbles

Clay pebbles are not used in all hydroponic gardens, but are most often found in gardens that implement the flood and drain method. With this method, plants are located in a pan, pot, tray, or bucket, and a mixture of nutrients and water is pumped in until the roots of the plants are submerged.

While the roots of the plants are flooded with the nutrient-water mixture, they absorb the nutrients and water that the plants need to grow. At the same time, stale air that the plants have already used is flushed out of the system. Then, after a set period of time the mixture is drained away and new, fresh air replaces it.

Clay pebbles are essential for many flood-and-drain systems because the pebbles give the plants a structure for stability. Instead of floating on the surface and then sinking to the bottom of their container, the plants remain in the same position when grown in clay pebbles.

To retain their round shape and allow water and nutrients to reach the plant's roots, clay pebbles are produced by firing round pieces of clay in a kiln. This process causes the clay to expand, which is why clay pebbles are sometimes called expanded clay pebbles. While they do not lose their shape when exposed to water, they do absorb and retain water, making them useful for hydroponic and other forms of indoor gardening.

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