A rain forest herb with large deep green leaves and white flowers, the peace plant or peace lily (Spathiphyllum spp.) is widely used as a houseplant since it tolerates low light levels. Not tolerant of frosts, it may also be grown outdoors in tropical shade gardens. A member of the aroid family, peace plant's flower comprises a finger-like spadix and a white cloak called the spathe.
Whether indoors or outdoors, the peace plant must not be exposed to direct sunlight, especially from 10 am to 4 pm, when rays are most intense. Bright indirect light is required to prevent leaf scalding, or browning of leaf blades. Outdoors the plant must be under a shade tree, awning or other covering. Indoor plants may be placed anywhere direct sunlight from a window does not directly touch the leaves or stems. This plant acclimates to dim light by north-facing windows in the United States.
Grow peace lily in a moist, well-draining soil or potting mix that has organic matter such as peat or compost incorporated. Water must fully drain from the roots and bases of leaves at the soil surface to diminish chances of fungal rot. Soil pH should be acidic to neutral (5.5 to 7.5).
Appreciating moisture, especially when temperatures are above 85 degrees Fahrenheit, water the soil only when it is dry in the top 1/2-inch. A evenly moist soil is ideal, and in an interior room where humidity is low and air temperatures almost constantly 70 degrees Farenheit, overwatering can quickly lead to a plant's demise. Make sure pots have drainage holes in the bottom.
Add a liquid houseplant fertilizer only in spring and summer at dosages listed on the product label. Outdoors scatter granular slow-release fertilizer, such as 10-10-10, across the soil in spring and summer while plants are actively growing and flowering. Granular fertilizer pellets may be used on houseplant instead of liquid fertilizing regimens. Err on the side of underfertilizing rather than overfertilizing indoor plants.
Remove errant stems or leaves with brown spots or holes with a knife or scissors, cutting at the base of the leaf stem. Trace the leaf stem to the base with your cutting blade to ensure you are pruning away the right leaf. As the white flower ages, it stiffens and turns green. You can remove them in like manner if you find them unsightly.
Repot the peace plant when roots grow out of the houseplant pot's drainage hole. Place it in a slightly larger pot, about 1 inch greater in diameter, using potting mix not top soil, to complete the planting task.