Good ol fashioned popped perlite volcanic rock. 4 cubic foot bags 36 bags to a pallet.
GROW!T Perlite Grade #4, 4 cu ft
PDF) Development of a defined compost system for the study of
Viagrow Horticultural Perlite, 1 Cubic Foot or 4 Cubic Foot
PDF) 242 Water, Nutrient, and Acid Requirements for Crops Grown
Perlite Medium/Coarse Grade - 4 Cu. Ft. Bag — Seven Springs Farm
Factors Affecting Production, Nutrient Translocation Mechanisms
Development of simplified agroclimatic procedures for assessing
Perlite - an overview
Plants, Free Full-Text
Silicon and Epichloë‐endophyte defences in a model temperate grass
Viagrow Horticultural Perlite, 1 Cubic Foot or 4 Cubic Foot
Mother Earth Perlite #4 - 4 Cu Ft HTG Supply Hydroponics & Grow
Enzymes and cellular interplay required for flux of fixed nitrogen
Agronomy, Free Full-Text
Compressed Coco Coir Perlite Mix, 4.5 KG/10 Lb