In floating garden, floating base is prepared from the roots of . . . . . . . .

In the floating garden, a floating base is prepared from the roots of Typha grass.
A floating garden is a planting on soil buoyed up (as on the surface of a lake) by rafts of interlaced branches or other floating support found chiefly in the Mexico City area and parts of Kashmir.
A floating base is made from the roots of typha grass or any other similar type of material. The floating base is kept in the water and seedlings are transplanted on leaf compost made out of the local vegetation growing in the area.