I tried to air-layer my RDB and it looked like it didn't work, So I took all the soil and potting mix out, didn't want mold to establish. I am going to use a plastic bottle and not girdle it, will skim off a little of the bark. Will look to do this near the cleft. So everyone has different success stories, let me know what pct of potting soil, dirt, perlite or ???? has worked for you. I am just trying to avoid creating mold issues, Thanks in Advance.