Which of the following materials is typically used in hydroponic systems?

In hydroponic systems, plants grow without soil, relying instead on nutrient-rich water solutions to provide the essential elements they need for growth. Perlite is a lightweight, sterile, and inert growing medium that is commonly used in hydroponics. It is derived from volcanic glass that has been heated to the point of expansion, resulting in small, white, and porous granules. These granules help to aerate the root zone, ensuring that roots receive adequate oxygen while still retaining moisture and nutrients in the growing medium.

Perlite is particularly valued in hydroponic systems for its ability to provide a well-draining environment, which reduces the risk of waterlogging and root rot, both of which can be detrimental to plant health. It is also sterile and does not contribute any organic material, minimizing the risk of diseases and pests that can come from using soil or compost.

In contrast, materials such as aerated soil, compost, and organic mulch are typically used in traditional soil-based gardening, where the soil structure and organic matter are essential for fertility and microbial activity. These materials are not suitable for hydroponic systems, where the focus is on a soilless environment that supports direct nutrient uptake through water.