Vermiculite is an incredibly useful growing medium. Horticultural vermiculite can be used for many beneficial purposes in the garden and can aid and assist in successful propagation, cuttings and plant raising.
One of the best uses of vermiculite is the plant propagation arena. Vermiculite is particularly useful when sowing fine to very fine seed. Instead of covering the seeds with a covering of compost, which can be very heavy on tiny seeds and can also form a hard cap, making germination very difficult, a small quantity of vermiculite can be used. This is very light and presents no restriction or check on growth, the seedlings can easily break the surface and, because of the lightweight granular texture of vermiculite, it does not form a cap on the top of the growing container or seed tray.
Vermiculite is also used widely in seed and potting compost mix, as well as with container plant pots, to provide a lighter, more friable compost mix.