Perlite

Perlite is made of small pieces of extremely porous volcanic rock. It is used to keep the humidity high. Cover the bottom of the grow chamber with perlite, and spray it with some water to maintain humidity.

Dictionary

A (2) | B (1) | C (3) | D (2) | F (3) | G (1) | H (2) | I (2) | L (1) | M (3) | O (1) | P (7) | R (1) | S (9) | T (1)