Peace lilies develop glossier leaves and bigger blooms when watered with rainwater instead of tap water, according to gardening experts at Prickle Plants. Tap water can be toxic to peace lilies because it contains fluoride and other minerals that clog the soil rather than hydrate the plant.
Why tap water harms peace lilies
The experts warn that fluoride in tap water is harmful to peace lilies, which naturally prefer rainwater. They recommend leaving a small watering can outside to collect rain and using that for watering. Tap water in some UK areas may contain higher levels of salts, minerals, or compounds such as fluoride, which is added to drinking water to protect teeth from decay.
Peace lilies grow naturally in tropical regions where rain contains few dissolved minerals, so they have not developed the tolerance that other plants have. When watered with tap water, fluoride and other minerals build up in the soil, and the plant cannot flush them out through its root system.
Signs of damage and how to water correctly
This buildup can oversalt the soil, making it harder for roots to absorb water over time. The plant becomes dehydrated, starting with brown leaf tips, then yellowing leaves, wilting, and eventually death. Rainwater contains lower fluoride levels, preventing mineral buildup and keeping roots healthy.
To water a peace lily properly, check the weather forecast and place a clean container outside whenever the plant needs water. The container can be placed in a garden, on a balcony, or on a secured windowsill, but not somewhere it could easily fall from a height. Put the peace lily in a sink, shower, bath, or another spot with drainage, pour the rainwater into the soil, and let the water drain out completely. Do not let the pot sit in water, as this can rot the roots. Once drained, return the plant to its usual location.
Using rainwater instead of tap water should leave the peace lily healthier, with perkier flowers and shinier leaves.
