Majorly there are 2 types of terrace gardens: one that we can establish on our terrace, balcony, etc.
And the other one is crafted against a hillside. A mountain is cut-down in garden beds along the slant to do agricultural farming.
It is very necessary that waterproofing must be done on the terrace to avoid seeping water Into the ceiling of the rooms below.
A proper drainage system must be there on the roof for rainwater and irrigation water to drain completely from the roof.
To make a terrace garden, one must keep in mind the space available also. It’s not like you just grow the flower on a terrace, balcony, or wherever and now there is no space left to go through.
If you have a large space on a terrace (say 8x8ft) dedicated to terrace gardening, then you can easily form flower beds in them to make them more attractive and beautiful.