>>1480977>>1480984I find that perlite is good for, "marking," soil. That way I can keep track of precisely what recipe I used to build the soil. I use colored aquarium gravel for the same purpose. A single bag can cover a huge area of soil for that purpose. Like if I attain a great amount of used soil from someone else's garden, I can toss in a couple handfuls of x color gravel to mark it. Then I can more easily keep track of it in the following years.
