Vermiculite is the name of a group of hydrated laminar minerals (aluminum-iron magnesium silicates) that look like mica. Vermiculite is generally a neutral 7.0 pH. It is very lightweight and mixes easily with other mediums like cocopeat, perlite, compost, and soil.
Benefits of Vermiculite
Vermiculite added to the potting soil increases water and nutrient retention and aerates the ground, resulting in healthier, more robust plants. Perlite may also be mixed in potting soils, but vermiculite is far superior for water retention.
Add vermiculite to the soil, either alone or with perlite, cocopeat, or compost, for conditioning and lightening. This will accelerate growth and promote anchorage for tender young root systems. Using vermiculite as a growing medium will help the plant more easily absorb the potassium, ammonium, calcium, and magnesium that are needed for vigorous growth.
How to use Vermiculite
If the native soil is heavy or sticky, mix vermiculite and soil in a 1:4 ratio.
For soilless medium or hydroponic medium use exfoliated vermiculite, perlite, and cocopeat in 1:1:3 ratio.