I undertook a grand adventure this weekend and made my own bonsai soil. Here's my story.
I purchased a 50 lb bag of Turface MVP, now called PrimeraOne by the distributer, for $11.75. I also picked up a 2 dry quart bag of Hoffman Volcanic Lava Rock for $4.99. An 8 dry quart bag of Hoffman Special Orchid Mix bark chips (screened Fir bark, screened hardwood charcoal, redwood bark) for $8.99. And an 8 dry quart bag of Hoffman Perlite for $8.99.
4.99 Lava Rocks
Screened out the Turface and was able to use about 20% of it. Rest will be used as cat litter. So $2.35 worth of usable Turface. Next, I had to smash up the lave rocks since they were about the size of peanut M&Ms. I wrapped a handful in a towel and hit them with a hammer. This took most of Saturday morning and my end result was about a quart of sifted rock. So I lost about half the rock volume, or $2.50. On Sunday morning , I worked on the bark chips. The bark was also quite large, so I used a [url=https://www.homebrewunderground.com/images/coffee-grinder.jpg]coffee grinder[/url] to make it smaller. I still have a lot of bark left, so no real loss there. Only used about 1/3 of the bag, so about $3 worth. I sifted the Perlite and about half the bag went into the compost heap. Of what was left, I used very little of it, maybe a dollars worth.
When done, I had about 5 quarts of soil. I was constrained by the amount of lava rock I had available. I spent a lot of money and a lot of time to make this soil.
So, here's my final recipe: (measuring unit here is a 16 oz plastic coffee can.)
1 Lava Rocks
Was it worth it? Still not sure at this point. It was fun to make, but I didn't end up with as much usable material as I wished I had.