Salvia is only propagated by clone, so you wont find any viable seeds.
It a very easy plant to grow and completely legal in some countries. It grows huge outdoors as long as you mist it a few times a day.. they don`t like really dry air..a humid forest would be ideal.
If the temp drops below 40F they`ll turn black and die..other than that they are very hard to kill
Here`s a few that live in my kitchen window, the one on the left is a 2 month old clone from the plant on the right.