Peace lily leaves turn yellow most often because of a watering problem, either too much or too little, but ageing leaves, too much light and poor water quality all cause it too. The trick is reading which one you are dealing with, because the fixes pull in opposite directions.
Yellowing on a peace lily (Spathiphyllum) is one of the most common questions we get. Below are the usual causes, how to tell them apart, and what to do about each.
Overwatering (the most common cause)
Peace lily yellow leaves are, more often than not, a sign of overwatering. If several lower leaves turn uniformly yellow and the soil is constantly wet, the roots are struggling. Soggy soil starves roots of oxygen and leads to root rot, at which point the plant cannot take up water properly however much you give it.
What to do: let the top 3 to 5cm of compost dry before watering again, and always tip away water that collects in the saucer or cover pot.
Underwatering and drooping
Peace lilies are dramatic when thirsty: they wilt hard, then yellow if left dry too long or too often. A plant that droops, gets watered, perks up, then droops again, and is shedding yellow leaves, is being left too dry between drinks.
Try water more consistently. Aim to water when the top few centimetres are dry rather than waiting for the collapse, since repeated wilting is what damages the leaves. Our guide on how often to water houseplants covers reading the plant rather than the calendar.
Too much light
Peace lilies are low to medium light plants. In direct sun the leaves pale, then yellow, and may develop scorched brown patches. If the yellowing is on the leaves facing a bright window, light is the likely culprit.
Try moving it out of direct sun to a spot with bright, indirect light or even a shadier corner. This is one of the few genuinely happy-in-low-light plants, which is part of why it is such a good office and bathroom plant.
Old age and natural yellowing
Not every yellow leaf is a problem. The oldest, lowest leaves naturally yellow and die back as the plant puts energy into new growth. If it is one or two of the bottom-most leaves at a time and the rest of the plant looks healthy, this is normal.
Simply trim the spent leaf off at the base. There is no need to change anything else.
Water quality and nutrients
Peace lilies can be sensitive to the chlorine, fluoride and minerals in hard tap water, which shows as yellowing with browning tips. A hungry plant that has not been fed in a long time may also yellow evenly across older leaves.
Try switching to rainwater or filtered water if your tap water is hard, and feed with a balanced houseplant fertiliser during the growing season. When you next repot, use a free-draining mix; our Spathiphyllum care guide covers the full routine.
How to Diagnose It Quickly
Feel the soil first. Wet and yellowing lower leaves points to overwatering. Bone dry with a history of drooping points to underwatering. Yellowing only on the sunny side points to light. One or two bottom leaves on an otherwise healthy plant is just age.