Hello there,
I am Sreenath, from India and currently reside at Kolkata which is a tropical area with Sea side within 100 miles, so its a place where its too humid during the summer and has moisture level throughout the Year.

So my main concern is that what will be the best soil mixture for my Bonsai. Currently they are growing in plain ground mud from the construction site. But, recently after a overview of the website, I was just able to collect a good amount of COCOPEAT, COMPOST, SAND GRIT and SAND.

So will these materials good for my Bonsai Plant?
Or should I change it according to what you say.

Plant Species that I have are:
1. Ficus Bengamina
2. Ficus Religiosa
3.Ficus Microcarpa
4. Ficus benghalensis
5. Indian Rosewood
6. Juniper
7. Gulmohar
8. Schefflera
9.Ficus Amplissima
10. Chinese Elm
11. Azalea
12. Prosopis Cineraria.

Please help me regarding this matter.

Thank You
Sreenath Chatterjee
Kolkata, India.

In general it helps to use a substrate that is well-draining. However in the area you live, it is always warm and moist if I remember correctly from the visits I have made to the area. You want to get lots of oxygen to the roots. So if you can find material to build a sieve, or find a sieve, go for a grain size of 2-5mm.

Thank you!
Okay so you are asking to mix my current soil with sieve of 2mm to 5mm

Actually I got some supplies of Vermiculite which is same as Akadama.
So can You help me send me a proportion of each of what I am using for my soil?

Thank You
Sreenath Chatterjee

This page has my mix: www.growingbonsai.net/characteristics-of-good-bonsai-substrate/