Perlite

Also known as: Expanded volcanic glass

Properties

pH effect	neutral / inert
Water retention	very low
Drainage	excellent
Oxygen to roots	very high
Bacterial surface area	low
Reusability	low (1-2 cycles)
Cost tier	low
Weight	very light

How it affects the system

Almost always used in a mix, not pure: pure perlite holds no water and dries out too fast for most crops
pH neutral and inert; does not buffer or affect water chemistry
Smooth glass surface: poor bacterial colonization compared to porous media
Compacts and degrades over time, eventually creates fines that clog drip emitters

System compatibility

Works well in:

drip
dutch bucket
wicking bed

Avoid in:

NFT channels
deep water culture (rafts)
media bed (ebb and flow)

Care notes

Wet perlite before adding it to a system, or you will breathe the dust; wear a silica-filtering mask when handling it dry, since perlite is largely silicon dioxide. It is a standard component of coir-perlite hydroponic mixes and is rarely used alone except in some Dutch-bucket setups for fast-draining crops like strawberries.

Crops that work in perlite

87 edible crops in the catalog list this medium as compatible.

Back to growing media reference

Properties

How it affects the system

System compatibility

Care notes

Crops that work in perlite

Further reading