There are two necessary components, Perlite and wormcastings. You can just use those, like a 50/50 mixture, or use 50 percent perlite and a mixture of wormcastings plus other stuff, such as peat or coco coir. You can also mix in natural mineral rocks and all kinds of other organic stuff. If you use a lot of wormcastings you won't have to add any fertilizer for about a month, and when you do add fertilizer you can use something like bat guano. Worm castings won't burn your plants roots like other sources of fertilizer. Bat guano and such things will burn your plants roots if you use too much though, so follow the directions carefully.