Status: 24.09.2023, 10:22 a.m.
By: Ines Alms
Expanded clay serves not only as a drainage layer and as a planting substrate for hydroponics. With a simple method, it helps even in small quantities when the room air is too dry.
Many houseplants, especially those that originate from originally tropical or subtropical rainforests, find it difficult to cope with dry indoor or heating air. Not only the drought of the potting soil, which is often associated with this, the plants also become more susceptible to pests. Very simple expanded clay from the garden centre ensures a better living climate and higher humidity.
Increase humidity for plants: using expanded clay as a home remedy
Expanded clay is a natural material that is often used for hydroponics. © agefotostock/Imago
Expanded clay is clay that is fired at about 1200 degrees Celsius, thereby increasing its surface area several times. Since the clay granules cannot compact as a substrate in a hydroponic pot, unlike the soil, the roots of the houseplants always get enough air supply and mold does not find a breeding ground. Because the clay inside hardly absorbs any moisture and conducts the irrigation water upwards on its surface, there is also no risk of waterlogging.
These properties can be used to increase the humidity in rooms. Ideally, this is 40 to 60 percent, but many plants can tolerate more. Expanded clay evaporates water on its surface as water vapor. My beautiful garden advises placing some expanded clay in a tray or planter as drainage and placing the houseplant on top. Then water is poured, but only so much that the plant does not come into contact with its roots. The evaporating water immediately supplies the plants with humidity.
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Spraying the plants with low-lime water, a room humidifier or an indoor fountain are also good ways to increase the humidity for plants in rooms.