Since you didn’t say why, what is the purpose behind placing the leaves upside down in the soil? At 0:38 -why not laying flat? If novice gardeners aren’t careful with watering, the leaves could easily rot that way. Any leaf of a plant that gets buried is eventually going to disappear and rot. Lol. Even though these are leaf cuttings, technically, the leaf shouldn’t die for a long time. I’ve grown baby plants from leaf cuttings that turned into large specimens, and the original leaf was still alive, attached to the plant. But if they’re in very rich soil, and even if they aren’t, leaves that are buried can be problematic… the part of the leaf that connects to the plant is where the new baby grows from. That should be closer to the soil anyway. If the leaf itself is buried, it will likely rot.