Screens for Screening Soils Question

[August44]

I have pumice that measures from 1/16 to 7/16. I am going to screen it and can screen with a 1/8" screen, a 3/16" screen, or a 1/4" screen. I have always done it with a 1/8" screen to get rid of the fines and anything below 1/4" and then just keep the rest for potting. I am wondering if I should be using the 3/16" screen instead. I'm not sure anything smaller than 3/16" is good for what I am doing, which is mainly conifers. It seems that the smaller the size, the wetter the product is, and it stays wet longer that the larger pieces, especially if it groups with other smaller pieces. I know its going to be more work as I will then re-screen the fines and keep 1/8" and bigger for some other project. Help and advice is appreciated. Thanks

 

[Shibui]

Another bonsai question where the answer is maybe.
Smaller particles definitely retains moisture more and less air but that may be good or bad depending on your watering regime and local climate. Nobody else has the same combination of factors so only you can decide which suits your growing conditions best and that will probably be through trial and error.