Vermiculite is well established as a growing medium. It is most commonly used in compost formulations, usually in combination with peat or coir. Vermiculite/peat or coir compost formulations provide ideal conditions for plant growth. The presence of vermiculite particles in the compost aids aeration, improves moisture retention and promotes the steady release of added fertilisers, whilst the vermiculite itself contributes potassium, magnesium and a number of minor elements.
The air/water ratios for vermiculite/peat or coir composts are ideal for the stimulation of root growth, and hence the production of healthy young plants. The vermiculite is sterile when processed. If stored correctly it will need no further treatment before incorporation into composts. Vermiculite can also be used as a carrier and extender for fertilisers, pesticides and herbicides. It is also used in a ground form for encapsulating seeds. Exfoliated vermiculite can also be used as a packing material for storing fruit, bulbs and tubers.