That is an option to get the lillies to grow if Bentonite is used. Could use container also I suppose and that would stop the lillies from spreading out of control. I am really trying to avoid using bentonite if at all possible. Hopefully the bucket test will prove it is not needed. I am already 2.5 times over budget on this project and bentonite would make it 3.5 to 4 times over budget.