Pumice is a cheap and readily available hydroponic media which is mined.
This porous volcanic rock allows for good water retention and aeration, and the use of a combination of fine and coarse materials allows a grower to manipulate the drainage capacity of the media.
Pumice can also be mixed with other types of growing media e.g vermiculite or coir, to improve aeration and drainage.
Pumice is slow to break down and is very lightweight. Its light-coloured appearance makes it an ideal media for summer growing as it does not attract heat.

Remarks:
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Prices are subject to change without prior notice.