My friend that struggles to grow mangosteens from seeds for years ,told me yesterday that he finally got the secret.
He says they really like high alkaline soil.
After googling informations in english about the soil requirements i found only contradictory studyes,that it likes rich fertile soil but it grows in poore red clay ferrosoils or that it doesnt likes alkaline soil but otther studyes sugest to apply gipsum and lime or else they get ,,translucent flesh disease,,.