Please consider these Suppliers and Guides for your gardening needs
Expanded Clay manufacturer:
1) Sizes: 2-4mm,4-8mm,8-10mm,8-16mm,10-30mm or as customized
2) Characteristic: Lightweight, insulating, strong,Extremely stable and durable,Non-combustible and fire-resistant
3) Usage: Hydroponics, Aquaponics, Cleaning filter, Structural concrete, Roof gardens, Light fill, Insulation
The other similar products are perlite,rockwool,vermiculite.
A gardening guide for green thumbs:
National Gardening Association