Hello and Thank you for the inquiry. Naja Grass for the most part grows floating. When it is growing very well, it sends roots downward toward your substrate to anchor itself and or to obtain more nutrients. Sometimes it will drop roots down toward wherever mulm tends to accumulate within your aquarium. I’ve also intentionally planted it in gravel and found that it will spread under gravel much like terrestrial grass. So really it is your choice as it seems to thrive either method. I find it does well without additional fertilizing when housed with Fish. Without additional live inhabitants I will occasionally, about once every 3 months add a golf ball portion of dried cow manure per 10 gallon aquarium. If the water starts to turn green either from the manure temporarily remove it or add Daphnia and Scuds.