Peace lilies are widely regarded as low-maintenance houseplants, yet a common watering mistake can prove fatal. Gardening experts at Prickle Plants warn that tap water, which often contains fluoride, can harm the plants and block up their soil instead of hydrating it.
Why tap water is harmful
One expert explained: "The fluoride in tap water can be harmful to peace lilies, and it would much prefer rainwater. The best thing to do is to leave a little watering can outside to collect rain, and use that when you water."
In some parts of the UK, tap water may contain elevated levels of salts, minerals, or compounds such as fluoride, which is added to drinking water to protect teeth from decay. Peace lilies naturally thrive in tropical regions where rainfall contains few dissolved minerals, so they have not developed tolerance to these substances.
When tap water is used, fluoride and other minerals can accumulate in the soil, making it harder for the roots to take in water. Over time, this oversalts the soil, leading to dehydration. Early warning signs include browning leaf tips, followed by yellowing leaves, wilting, and eventually the plant's death.
How to water peace lilies properly
Rainwater is significantly better for peace lilies because it contains lower fluoride levels, preventing mineral buildup and keeping the roots healthy. To collect it, check the weather forecast and place a clean container outside whenever watering is needed.
Ideally, position the container in a garden, although a balcony or windowsill will work as long as it is secured safely and cannot fall from height. When watering, place the peace lily in a sink, shower, bath, or another spot with proper drainage, then pour the collected rainwater directly into the soil.
Ensure the water drains completely from the pot, as pooling can lead to root rot. Once all excess water has drained, return the peace lily to its usual position. With this simple switch from tap water to rainwater, the plant should soon show perkier blooms and glossier leaves, as mineral deposits are prevented from building up in the soil.
