Vermiculite

Vermiculite is, like perlite, another mineral that expands through overheating to lightweight pebbles. It contains more water than perlite and has a natural characteristic that can be compared to the functionality of a wick: It absorbs liquid and then lets it drain again slowly.



Due to this characteristic, it can bind water and nutrients in a passive hydroponic system. If the plant roots are surrounded by too much water and an insufficient amount of air, it is possible to decrease the water retention of the medium stepwise by adding continuously increasing amounts of vermiculite.