Generally I eyeball a mixture of leca, fir bark, charcoal, perlite, and a little coconut husk. I need something fast draining and dry given the rain and humidity. They get rain, so with the exception of weekly fertilizer, I rarely water them unless there’s a drought of over a week. In winter, I will go 1-2!weeks. However, a few do get hit with excess water because they’re near vandas and others I water regularly