The peace lily (Spathiphyllum) is one of the most popular houseplants. Its ability to adapt to poorly lit indoor conditions stems from its native habitat of the rain forest's floor. It grows white flowers called spathes and long, wide dark green leaves. A common problem when growing peace lilies is brown-tipped leaves, which one or a combination of factors can cause.
Overwatering or Underwatering
Figuring out the appropriate amount water to give your peace lily may be the most difficult part of a peace lily's care. The soil should be constantly moist but never soggy. You also want to steer clear of water containing chlorine as this can cause plant damage as well. A thorough watering once or twice a week should suffice. Some gardeners choose to wait until the leaves start to slightly droop before watering, but be careful not to wait too long as this can cause significant damage.
Optimum temperature for peace lilies ranges between 68 and 85 degrees Fahrenheit during the day and slightly cooler at night. Extended exposure to temperatures below 40 degrees Fahrenheit result in plant damage including brown leaf tips. If kept indoors, keep the peace lily out of the way of air conditioning vents and drafts.
Overfertilizing peace lilies is another cause of brown-tipped leaves. Peace lilies don't require much, if any, fertilizing. If you do fertilize your peace lily, do so four times a year with a diluted, balanced, water-soluble fertilizer such as 20-20-20 to keep your peace lily's leaves green and supple.
Peace lilies' native habitat is one of high humidity. The indoor air is often too dry for peace lilies to thrive in and supplemental techniques are required. When a plant doesn't receive enough humidity, the leaves turn brown at the tips, and the peace lily is no exception. Fill a sterile spray bottle with clean water and spray the peace lilies' leaves several times a week. Another option is to pour water over a tray of pebbles or lava rocks and set the peace lily on top of the rocks. As the water evaporates, a curtain of humidity surrounds the plant. An electric humidifier is another option for peace lilies that are kept indoors.