Peace Lily Yellow Leaves: Read the Pattern, Then Fix It

Yellow leaves on a peace lily are a signal, not a diagnosis. Iowa State University Extension notes that yellowing, browning, and leaf drop in houseplants often come from several factors together. So look at the pattern before you change anything.

The two questions that settle most cases: is the mix wet or dry, and where on the plant and leaf is the yellow?

Read the pattern

What you see	Most likely cause	Source
Lower and inner leaves yellowing, mix wet	Overwatering	University of Maryland Extension
Yellow on new and old leaves, soft stems, sour-smelling mix	Overwatering, possible root rot	Virginia Cooperative Extension
Plant wilted, leaf edges turning yellow, mix dry	Mix allowed to dry too far	Clemson Extension
Yellow edges soon after feeding, brown tips	Too much fertilizer	Clemson Extension, NC State
Yellow between the veins, veins stay green	Magnesium deficiency	Clemson Extension
Pale or bleached patches on the window side	Too much sun	Maryland Extension, Clemson
Yellowing and leaf drop after a cold move or near a door or vent	Cold or hot drafts	Iowa State Extension, NC State

Overwatering and root damage

The University of Maryland Extension guide to nonliving indoor plant problems calls wilting or yellowing of lower and inner leaves a primary symptom of overwatering. Virginia Cooperative Extension’s watering guide adds yellowing on new and old foliage, mushy leaves and stems, rotten-smelling mix, and fungus gnats.

Clemson Cooperative Extension’s peace lily fact sheet warns never to let the plant sit in excess water, because this leads to root rot.

What to do:

1. Stop watering and empty the saucer or outer pot.
2. Slide the plant out and check the roots. University of Maryland Extension describes rotted roots as brown to black and soft, with an outer layer that pulls away from the core.
3. If most roots are firm, return the plant and let the mix dry slightly before watering again.
4. If many roots are soft, cut them off and repot in fresh, sterile mix in a clean pot, as Maryland Extension advises.
5. From then on, follow Clemson’s guidance: keep the mix moist but not soggy, and let it dry slightly between waterings.

Underwatering

Clemson notes that when the mix dries excessively, the plant wilts and the leaves and edges turn yellow. Virginia Cooperative Extension lists dry potting mix shrinking from the pot edge, a light container, and brown tips or edges as signs of underwatering.

What to do: water until the whole root ball is wet and water drains out. If the dry mix sheds water, give two or three slow applications, as the Virginia guide recommends. NC State Extension notes that watering from below works very well for peace lilies. Do not leave the pot standing in water for more than 60 minutes.

Fertilizer: too much or too little

Clemson lists overfertilization as a cause of yellow leaf edges, and says overfertilizing turns leaf tips and roots brown. NC State warns that over-fertilizing and salt build-up can burn leaf tips and roots.

• Clemson recommends a balanced liquid fertilizer such as 20-20-20 every six to eight weeks in spring and summer, at one-quarter of the recommended strength.
• NC State also recommends one-quarter strength, and flushing the mix with plain water between applications.
• If you have been feeding heavily, stop and flush the pot with plenty of water.

Too little feeding can also yellow leaves. Iowa State notes that under-fertilized plants often develop yellow leaves. Clemson notes that magnesium deficiency yellows the tissue between the veins while the veins stay green.

Light and temperature

Maryland Extension notes that strong sun and heat cause pale, bleached, or faded areas. NC State says not to place peace lilies in direct sun, and Clemson recommends bright indirect light. Move a sun-damaged plant back from the window. Our peace lily sunburn guide covers this in detail.

Iowa State notes that leaves are likely to yellow and drop if a plant was not protected from cold in transport, or gets blasts of cold or warm air from doors, windows, or ducts. It also links sudden changes in light intensity to leaf drop, and advises changing light levels gradually.

NC State gives peace lilies 20–29 °C (68–85 °F) by day, with a night drop of no more than about 6 °C (10 °F). It warns that long periods below 4 °C (40 °F) can damage leaves, stems, and roots. Clemson advises avoiding temperatures below 16 °C (60 °F) and keeping the plant away from heating and cooling vents.

Root-bound plants

Maryland Extension notes that pot-bound plants tend to dry out too fast, with brown or dead leaf tips. Clemson suggests repotting when roots grow through the drainage holes or circle on top of the mix, into a pot 2.5–5 cm (1–2 in) larger. NC State recommends repotting, when necessary, in February or March, and keeping the plant somewhat pot-bound.

What to do with the yellow leaves

Yellowed leaves are damage already done. Cut them off at the base once they are mostly yellow, using clean scissors. Judge whether your fix worked by the new leaves, which should come in green and firm.

If yellowing keeps spreading after you have corrected watering, light, and feeding, look again at the roots. For a plant that has collapsed, see our peace lily drooping guide. For routine care, see the peace lily care guide and the peace lily hub.

References

• Clemson Cooperative Extension, Home & Garden Information Center: Peace Lily
• NC State Extension Gardener Plant Toolbox: Spathiphyllum
• University of Maryland Extension: Indoor Plant Problems - Nonliving
• Virginia Cooperative Extension: Properly Watering Container Houseplants (SPES-804)
• Iowa State University Extension and Outreach: What causes leaves on my houseplant to turn yellow or brown and drop off?
• University of Maryland Extension: Root Rots of Indoor Plants