In the professional horticulture, the top priority is safety. To produce a safe substrate, we need safe raw materials.
It is for that reason that the information of your base materials should be clear:

• Is the material uniform?
• What is the chemical analysis?
• What is the physical analysis?
• Are there weeds in your raw material?
• Is the material stable or does it break down easy?
• What is the availability?
• How proper is the production site?