If you've ever seen a peace lily growing in a pot with a beta fish, then you've seen a novelty plant. Most peace lilies grow in soil, and like to almost go completely dry between waterings. A peace lily that is grown in water is one that has adapted to an extreme growing condition by developing multiple tiny roots that feed the plant rather than larger roots for taking nutrients from soil. Lilies that are grown in water tend to be shorter lived than their soil-growing cousins. If you are going to grow a lily in water, it is best to purchase one that is already growing in water and has developed the root system ideal for those conditions.
Fill your glass container with tepid distilled water. Never use tap water, because the chlorine, fluoride or hard water minerals that may be in it will harm the plant.
Cut a hole in the center of the plastic stopper to hold your peace lily in place at the mouth of your glass container.
Remove your peace lily from the container that you purchased it in. Examine the roots for rot or damage and remove these roots with a pair of garden shears.
Gently insert the peace lily into the plastic stopper and place the plant's roots into the glass container. Check to ensure that the roots are completely submerged in the water.
Feed the plant with a few drops of liquid fertilizer once every two weeks.
Change the water in your peace lily once every two weeks. Never allow the roots to be out of the water or dry out. This will damage them.
Place your lily out of direct sunlight. Peace lilies love indirect sunlight and will even thrive in homes or offices where little light is present.