Vermiculite is a super absorbent growing medium that evenly distributes water using capillary action. Think of it as the gardening version of a sponge. It is a naturally occurring mineral that expands when heated, forming layered, absorbent strands.
Main features of vermiculite
pH neutral
Light weight
Water absorbent
Great at absorbing nutrients
Evenly distributes water
Good drainage
Using vermiculite in hydroponic growing
Vermiculite is a staple hydroponic medium because of its great water and nutrient retention. It can be used in wicking bed systems, or as the growing medium in net cups for NFT systems.
Using vermiculite for indoor plants
Some indoor plants are thirsty and thrive in moist soil. Mix vermiculite with soil at about 70/30 (soil to vermiculite) to increase water retention. Plants that need more moisture may suit a 50/50 mix.
Using vermiculite in propagation
Cuttings can be placed directly in moist vermiculite. It gives more root aeration than water alone, and stems are less likely to rot.
Using vermiculite for seed sowing
Seeds of all sizes can be grown in vermiculite. Fill a container that has drainage holes, soak the vermiculite in water and sprinkle seeds over the top. Cover larger seeds (bigger than a grain of rice) with a light 1cm layer. Once seedlings emerge, give them sunlight or an LED grow light.
