Japanese Elm Care Guide
For proper Japanese Elm Care just follow these basics and listen to your tree =). The Zelkova - Japanese Elm is an outdoor tree, can be kept indoors but will need a few hours a day of direct sunlight or allot of fairly strong indirect sunlight. If you have a window that gets good light that would work and keep the tree away from drafts. Outdoor is preferable though. The tree prefers much light, but strong direct light can burn the leaves.
Water regularly as usual, but let it dry out between watering. Use a good free draining bonsai soil like Akadama, or Lava Rock, Perlite, and a little bit of pine bark and grit.
Re pot your bonsai once every year or two, less often when the tree matures, using a basic Bonsai soil mixture. Here is my Youtube video walking you through a Japanese Elm - Re Potting Re Potting Your Japanese Elm Zelkova