Being new to Bonsai, I was wondering if someone could clarify soil particle sizes for me. After watching some Bonsai Mirai and reading the soil primer on RMBS web site, it seems to be that there are typically two ranges used: 1/8”-1/4” and 1/16”-1/8” and that generally everything that falls through a 1/16” screen is fines that is thrown away and everything that stays above a 1/4” screen is generally also not used in most soil mixes.
Am I understanding that right? If not, what is the upper limit of size when one talks about 1/4” particle size, as generally you sift for a range between two screens. It’s confusing (as a beginner) to talk about discrete sizes of particles like the RMBS soil primer does, since it seems more common to sift between screens and have a range of particle sizes.
I got further confused when I opened the pumice that arrived via the club order and found that it is all extremely large and maybe only 10% of the bag falls through a 1/4” screen. Mostly seems unusable to me, unless I’m just way off base in my understanding of these particle sizes. The lava that arrived fell 95% between the 1/4” screen and 1/8” screen and is more along the lines of what I was expecting.