This is to give the plants the good drainage that they need.
All species need good drainage and protection from the cold.
In almost all cases, beds were raised to provide good drainage.
It is a flat zone, and has the natural conditions for good drainage.
The pot must have holes in the base for good drainage.
The species requires good drainage and protection from direct sun.
It requires good drainage and needs little water once the roots are established.
Tulips require at least six hours of sun a day and good drainage.
The lower layers were of small stones that allowed good drainage.
This species can grow in a range of soil types so long as they provide good drainage.