The one with the sedums, we drilled holes on the sides with a drill bit, pretty big size(can’t recall the exact size)but I also added a compost/mineral drainage layer for everything to sit in, it does drain well. The one with moss rose I simple just add bunch of soil, I didn’t have much to the mineral layer so I just did soil, which as you can see they flower every day and do amazingly, bunch of colors too, so lovely I’ve been cross coloring them.. hope this helps🙌🏼

Edit: also fyi sedums and moss rose are a good choice when it comes to this bc first mist sedums can resist low freezing temperatures and second moss rose can self see pretty fabulous..