i planted as i was initially filling my tank.. lots of stem plants are good for the cycle even if you don't plan to keep them, i know some people just float the extras. i had a bunch of water sprite, wisteria, anacharis, stuff like that, and they exploded with growth during the cycle at 2wpg. i ended up adding fish during my 5th week. its nice too because your plants are about filled in and coloring up at the time you begin to stock.