What to do if your Peace Lily has yellow leaves and brown spots

Quick diagnosis

Your plant appears to be a Peace Lily (Spathiphyllum floribundum). The main symptom is localized yellowing on some leaves and a dark brown spot on the edge of one leaf, while the rest of the foliage is green and no visible pests are present. This indicates localized stress—likely from irregular watering, sunburn, or inappropriate humidity conditions—and not a widespread infection.

Most likely causes

• Irregular watering: the substrate dries out too much between waterings and then may receive heavy waterings that cause fluctuations.
• Exposure to intense direct light or a heat source that scorches leaf edges.
• Low ambient humidity causing tip and edge desiccation.
• Salt buildup in the substrate or recent excessive fertilization leading to edge spots.

Signs to watch for

• New brown spots spreading from the edges toward the center.
• Increased yellowing on more leaves.
• Appearance of rot at the base of the stem or root ball (unpleasant smell, soft tissue).
• Presence of pests (although none are observed now, check periodically).

Solutions and practical care

Watering

• Keep the substrate slightly moist: allow the top 2–3 cm (about 1 inch) to dry before watering again. Avoid keeping the substrate continuously waterlogged.
• Check the pot drainage: if water pools, consider switching to a pot with a drainage hole and a mix that drains well.

Light and placement

• Move the plant to a spot with bright, indirect light. Avoid strong direct sun (especially mid-day sun near south- or west-facing windows).

Humidity

• Increase ambient humidity: mist the leaves in the morning 2–3 times a week or place a tray with pebbles and water under the pot (without letting roots sit in water).
• Try to keep relative humidity above 40–50% if possible.

Substrate and fertilizing

• If the pot hasn’t been refreshed in more than 2 years or salt buildup is suspected, consider repotting in spring into a humus-rich, well-draining mix, provided the roots are healthy.
• Avoid heavy fertilization until the plant recovers. If you fertilize, use half the recommended dose and a balanced indoor fertilizer every 4–6 weeks during the growing season.

Checklist for the next 1–2 weeks

• Watch for new spots or spread of yellowing.
• Check substrate moisture every 2–3 days and adjust watering accordingly.
• Monitor new leaves to ensure they emerge with normal color and texture.
• Periodically check for pests.

When to seek additional help

If spots increase rapidly, signs of rot appear at the base, or the substrate smells bad, request a more detailed review: it may then be a root problem or an infection requiring specific intervention.

With simple adjustments to watering, placement, and humidity, most Peace Lilies recover well. Keep observing over the next few days and act according to the checklist to prevent the damage from spreading.