Thankfully, I don't have problem with roots growing, only with roots growing in wrong direction
I am also growing bonsai, and one one forum a guy suggested me to sprinkle bonsai tree with light beer (50-50 beer+water) as it helps leaves accumulating vitamin B for its cells. He also said he is doing that for his orchids and that they have beautiful shiny leaves. Now, I still didn't make beer party for my plants, but I will test bonsai first. If it goes well, orchids will get their share too, and then I am going to share the results with the rest of community.