Hello, begonia enthusiast! I'm so happy you've chosen to add this beautiful plant to your garden. I know you'll adore it! Now, let's take a look at the soil. This particular begonia, the amphioxus, does best with soil that drains well and has a pH of about 5.5 to 6.5, but there are many options. If you're feeling creative, you could even try a tropical and orchid plant mix! Or, if you're more into a DIY approach, you can use a soil mixture like perlite, vermiculite, peat moss, and charcoal.