Murraya paniculata & Antidesma bunius

Hello IBC!

    I have acquired Murraya and Antidesma materials three days ago. since river sand is not available in our area. i planted them on concrete sand about 2-3 mm in diameter, and i put some "ipa" or palay husk after the first layer of the coarse sand. i soaked all of the materials in rooting hormone (hormex) and then planted them above the ipa and covered the roots with more sand. then i covered them with plastic so that moisture will not escape. So my question is that. IS THAT METHOD OKAY?? . My first material is premna odorata and i planted it using this method and it is thriving now. but for these materials I'm not quite sure because I'm just a beginner in bonsai and its my first time to handle these species. comments and suggestions are much appreciated guys.