Will this help my aquarium Plants?

will my aquarium plants grow faster if i put sand on the bottum layer and then the rock pebble things on top? will that help the roots to spread at all? my plants are doing fine and staying green and healthy but they aren't expanding or growing any bigger so will putting sand help? also my red eye tetras are eating one of the plants leaves off. This is a really dumb question but can i get them to stop somhow? lol