Begonia

Getting your begonias to grow is relatively straight forward.

As I've said before, my way isn't the only way, you have to figure out what you prefer.

I grow my begonais in free-draining soil, from day one.   Most of them thrive in moist soil, indirect light and humidity.

If it is a single leaf, I am propagating, I tend to plant them quite deep, or reduce the stalks length, so the leaf is near or touching the soil.  It's annoying when sometimes they decide to send out plantlets from the top of the leaf and then suffer.  This growth on a long stalk, can often amke the stalk snap too.

If it is a cutting, I would ensure that the node is buried in the soil.   The plantlet will emerge in time.  

If it is a thick stem cutting I leave them to callus before potting up.   Eg Begonia carolineifolia, which is a rhizomone begonia, I cut into segments, callus, then pin down, barely covered in soil.   These store water in their stems, so do not overwater them.

Some begonais, although they love humidity can also be susceptable to powdery mildew.  This is especially true of the Rex begonias.   

There are three main categories: fibrous-rooted, rhizomatous, and tuberous begonias.  Roughly ....

Fibrous - Begging begonias, Cane (angel wings), shrub, tailing and thick stemmed

Rhizomatous - Rex, carolineifolia, bowerae, cleopatrae, manicata, masoniana, prismatocarpa, and versicolor.

Tuberous - Those ones you buy as bulbs near summertime.       Semi-tuberous - eg dregei, with the swollen stems.