Vermiculite is applied mixed with the substrate or on the surface to maintain the temperature and humidity in germination and throughout the crop.
Vermiculite has some very interesting properties in gardening. such as its great absorption of water and its high CIC. Its water retention can become a problem if the mixture contains a high proportion of vermiculite. so the percentages in volume are usually around 5% maximum.
It consists of mixing a little vermiculite (2% by volume) when peat is used alone. The peat. when it dries. It is difficult to rehydrate. The humidity retained by the vermiculite prevents the total drying out of the peat so rehydration becomes easier.
Its light weight makes Vermiculite a very comfortable product to use.