Perlite is one of the most popular hydroponic growing mediums, commonly found in a 50/50 mix with vermiculite. This mined material was originally used as an additive to aid aeration and improve soil drainage. It is derived from volcanic glass with holes throughout created by water bubbles popping at high temperatures.
Advantages of growing with perlite
Perlite is an excellent choice for wick type hydroponic systems. Its aerated nature gives it good wicking action. Perlite is a popular choice because it is inexpensive and readily available.
Disadvantages of growing with perlite
Perlite does not retain water well and must be watered frequently. It is not a good idea for a garden that will be unattended for long periods of time. Perlite can also be hazardous to your health if you breathe the dust. Always wear a mask when working with perlite.