For some, peace lilies (Spathiphyllum spp.) are among the simplest houseplants to maintain, often thriving despite neglect. However, others find them challenging to care for properly. Spathiphyllum species are certainly particular, which may pose difficulties for those with varying plant care routines. Despite this, the watering preferences of peace lilies are quite similar to many other plants. The difficulty may arise from being new to indoor plant care or the emotional connections often associated with acquiring peace lilies, such as during funerals or illnesses.
Nonetheless, the essentials of watering—when and how—are straightforward to master. A common mistake is using the “let it droop” method, which stresses the peace lily and can result in discolored and unhealthy leaves. Since water needs are influenced by factors like season, light, temperature, pot size, and more, it’s best to water peace lilies when the soil reaches the right dryness level. Allow the top 2 inches of soil to dry out, then water the peace lilies until water flows out of the drainage holes. Ensure you water before they begin to droop, typically 10 to 12 days after the last watering.
Water is an important part of watering
If you’re accustomed to growing hardy annuals and vegetables that aren’t picky about water quality, you might be surprised by how particular peace lilies can be about their water. They seem more sensitive to chlorine than most houseplants, and some believe they react to fluoride as well. Therefore, consider using filtered or purified water to avoid the negative effects of tap water on these plants.
It’s possible to overdo it, though; while distilled water isn’t necessary for plants, letting tap water sit for a day allows volatile chemicals like chlorine to evaporate. Filtered water that removes chlorine, reverse-osmosis water, and untreated well water are all suitable. While opinions vary on rainwater, most agree it’s fine for Spathiphyllum species. Avoid using straight tap water regularly, and don’t habitually water with bottled water.
Since peace lilies are sensitive to cold and sudden temperature changes, avoid using cold water, which can shock the plant’s roots. Room temperature or lukewarm water should suffice, aiming for water no more than 15 degrees cooler than the surrounding air temperature.
But what’s the water actually doing in there?
Peace lilies dislike being in standing water. Like most plants, the Spathiphyllum genus prefers moist, well-drained soil but particularly dislikes wet soil, emphasizing the “well-drained” aspect. Achieving this in a pot can be challenging.
One issue is the soil. Using a potting mix that retains too much water can worsen any over-watering or even appropriate watering. Opt for potting soil with the right structure and organic material to retain water—since you’ll be checking for soil dryness anyway—and avoid water-retentive amendments.
Use a pot with drainage holes, and avoid adding materials like gravel and pot shards to encourage drainage. The transition from soil to shards can actually hinder drainage, and drainage material can occupy too much space. The bottom zone of soil in the pot is already too wet for a peace lily’s roots (known as the perched water table), so adding drainage material can reduce the available root space.
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