What type??
ADA Aqua soil is great for creating bottom coverings ... i have it in my shrimp tank which is planted with various plants and moss and i have never added any fertilizer and nothing has ever died ... once the ADA soil is in, it does not have to be cleaned like gravel and plants will to well in it ... my tank even has minimal light and the plants still thrive ...
http://www.adgshop.com/Aqua_Soil_s/21.ht ...
Grass?
You mean tank moss/plants? No soil,
Depending on the type, normal gravel or tank sand.
