Join Date: Nov 2018
Location: Oil City PA. USA
If the plants are rooted you can plant them in the sand just like any other substrate. I would put plant tabs by each plant and use Flourish supplement ( The way it says in the directions on the bottle. If the plants are rhizome plants like Java fern and Anubias then do not plant these plants and bury them in the sand just plant the roots and leave the rhizome above the substrate. Or leave these plants float. (With the Java fern you could yse a plant weight to hold it in place on the top of the sand and let the roots grow into the sand on their own.
And yes you could plant the potted plants leaving them in their pots but I really don't recommend it. The plants roots in a pot have to grow and expand just like a flower or a plant you would plant out side.
With the right water parameters, PH, lighting, and Ferts You will find the plants do very well in the sand.
All of my tanks have sand and are heavily planted. The plants thrive with the right care.