I'm setting up a brand new planted tank (dirted capped with sand).

Should I fill it with water than plant, or plant before filling?

Thank.

I do a mixture of both. I did dwarf sag in my last tank, so I filled the tank with about 2-3 inches of water and planted the dwarf sag. Then I filled it about 6-8" and planted some short swords, anubias and other small plants. Then I filled it about 18" and planted my large swords. I topped the tank off and I was done.

I prefer to plant before filling all the way. I fill until it is an inch or two above the substrate then plant. This also helps stop plants from floating up before you've got the roots covered. I find starting with the shorter plants easier as the taller plants get in the way.

Exactly wht i do except just put enough water to cover the substrate. Because i use dirt and sand i keep some sand aside to fix those plants that would want to float away as i fill the yank

I like to fill the tank up halfway before planting then fill the remaining water to flood it.