The soil used for bonsai in Chennai is very different from what we use in Australia. It is a mixture of red clay, sand and cow manure. Some growers add broken low-fired red brick for better drainage. The sand used in the mix is rather small grain, like the one used for mixing concrete. While we in Australia make our soil mix for drainage, they in India make their soil for water retention. The climate in Chennai can be very hot and dry. Never the less, bonsai growers in Chennai complain that their trees grow too fast! Needless to say, clay and manure provide their plants with ample nutrients. High temperatures all year round don’t allow the soil to be saturated with water for too long, especially in a shallow container. I also think that native plants of Tamil Nadu are adapted to waterlogged soil during monsoon and very dry soil in summer. The soil is too sticky when wet and for repotting they use dry soil mix (see image below).