How to Water Peace Lilies. Peace lilies need consistently moist soil, but they definitely don't like to sit in standing water. Whenever the top inch of soil is dry, water the plant until the overflow starts to come out of the bottom of the container. Wait until it stops draining, then set the pot back in its saucer.
When it comes to fertilizing a peace lily, any good quality, water-soluble houseplant fertilizer is fine. Look for a product with a balanced ratio, such as 20-20-20, diluted to one-half or one-quarter strength. Be sure to water after feeding your peace lily to distribute the fertilizer evenly around the roots
Light: Peace lilies prefer light partial shade, and can tolerate fluorescent lights. In fact, some have been known to thrive in rooms with no windows at all. Yellowing leaves indicate that the light is too strong, and brown leaves or streaks indicate scorching from direct sunlight
Peace lilies prefer warm daytime temperatures between 68 and 85 °F and nighttime temperatures about 10 °F cooler. Try to avoid temperatures below 60 °F as cold damage may occur. These plants need very little fertilizer.
Place the peace lily in the new container. Fill in around the root ball with potting mix, then firm the mix gently with your fingers. Water lightly to settle the soil and then add a little more potting soil, if needed. Again, it's important to situate the plant at the same level it was planted in its old pot.