10 Common Causes of Peace Lily Leaves Turning Yellow

I find peace lilies to be generally low-maintenance houseplants, but it can be a big worry if the leaves start turning yellow. Peace lily leaves may turn yellow due to various environmental factors, but the most common reason, in my experience, is overwatering or underwatering. Other causes include poor water quality, aging foliage, or a lack of nutrients in the soil. Incorrect light levels, changing temperatures, and low humidity can also cause yellow leaves.

1) Overwatering

Yellowing peace lily leaves can be one of the main signs that the plant is being overwatered. Other symptoms of overwatering include brown tips on the leaves and wilted foliage. If not dealt with, overwatering can lead to other problems like root rot, fungal diseases, and pests.

Peace lilies, also known as Spathiphyllum, grow in moist conditions within the jungles of Southeast Asia and South America. But although they prefer moist soil, they hate being waterlogged. Use your finger to check the soil. If it feels very wet, then the plant is being overwatered.

Peace lilies benefit from a regular watering schedule of approximately once per week. To avoid issues like overwatering, I give the plant a drink when the top inch or two of soil feels dry

2) Underwatering

Underwatering can be another cause of yellowing peace lily leaves. Although peace lilies don’t like being waterlogged, they won’t tolerate dry soil either. These aroids need fairly moist soil and should be watered about once per week.

You’ll need to perform some detective work to determine if the yellow leaves are caused by overwatering or underwatering. Use your finger or a hygrometer to test the soil. If it feels dry or is pulling away from the edges of the nursery pot, your peace lily is underwatered.

Prevent underwatering by giving your peace lily a good drink when the top inch or two of growing medium feels dry.

3) Old leaves

If just one or two of the lower leaves of your peace lily are turning yellow, it’s usually nothing to worry about. As these plants age, the older foliage naturally turns yellow and drops off. When the older leaves expire like this, the peace lily can focus on new growth.

If the older leaves start to turn yellow and wilt, simply remove them. Use clean scissors to cut these yellow leaves at the base of the stem where it meets the main plant. If these old yellow leaves fall onto the soil, clear them away to prevent any pests from moving in.

4) Incorrect light levels

Another possible cause of yellowing leaves on peace lily plants is exposure to incorrect levels of sunlight. Peace lilies thrive on the forest floor of tropical jungles and often receive dappled shade rather than direct sunlight.

As houseplants, peace lilies do best in bright indirect sunlight and some partial shade. North or east-facing rooms are ideal locations for these plants. If given too much direct sunlight, peace lily leaves essentially get bleached yellow. Variegated peace lily plants can be particularly susceptible. Brown spots or streaks on the foliage are another symptom of too much light.

Too much shade can also turn peace lily leaves yellow because the plant can’t get enough light to perform photosynthesis. This means that the peace lily can’t feed itself.

5) Temperature fluctuations

Peace lilies are low-maintenance plants, but they can develop yellow leaves if they’re exposed to fluctuating temperatures. Peace lily plants prefer temperatures that stay in the range of 55 to 85ºF (12 to 30ºC). If temperature stress sets in, then yellow leaves can be a clear symptom.

My peace lily plants don’t like cold or hot drafts from air vents, windows, or radiators. Keeping them away from drafty areas helps keep the temperature stable. If the temperature gets too high or too low, the peace lily will develop yellow leaves in response.

6) Lack of humidity

As natives of tropical jungles, peace lily plants thrive in humid conditions. When grown indoors, an average humidity level of around 60% is ideal for peace lilies. However, if the air around the plant gets too dry, it can cause yellow leaves.

Check if the leaves have brown tips to work out if the yellowing of peace lily leaves is due to low humidity. This is usually down to low humidity or underwatering. You can boost the humidity around the plant with a humidifier or a pebble tray. You can also mist the peace lily every few days or situate it in a steamy bathroom.

7) Water quality

Ensure good water quality when watering houseplants like peace lilies. Using tap water can cause problems like yellowing leaves, which is caused by chemicals like fluoride and chlorine.

If the leaves of your peace lily are turning yellow, look at the soil. If you see white dots sprinkled throughout the soil, that can be a buildup of salts from low-quality water. To remedy this, use filtered or dechlorinated water when watering your peace lily.

8) Lack of nutrients

Like all plants, peace lilies need good nutrient levels in their soil to fuel new growth. Yellow leaves can signify that your peace lily isn’t taking in enough nutrients. This is usually caused by a lack of nitrogen in the soil, which powers photosynthesis.

Peace lilies that are deficient in vital nutrients often exhibit yellow or wilting leaves and weak growth. To boost the nutrients in the soil, use a diluted houseplant fertilizer every six to eight weeks. You can also refresh some of the growing medium with a fresh mix to top up nutrient levels.

9) Repotting shock

If peace lily plants have been recently repotted or transplanted, it can take time to acclimate. This can cause some of the leaves to turn yellow through shock. In general, peace lilies only need to be repotted once a year because they grow fairly slowly.

Peace lilies that have yellowing leaves that don’t have brown tips are likely suffering from shock. Water the plant as you usually would but keep it in some partial shade until it recovers. It’s also a good idea to avoid fertilizing the plant until it has recovered.

Only repot peace lilies if they are rootbound. Check the holes in the nursery pot. If roots are visibly peeking out of the holes, the plant is ready to be repotted.

10) Diseases or pests

Although they’re relatively hardy against diseases and pests, peace lilies can still develop infestations. Fungus gnats, mealybugs, scale insects, and root rot are the most common problems. In most cases, the activity of these pests can cause yellowing leaves.

Root rot is caused by a lack of airflow around the roots due to dense soil. This means that the plant sits in too much water, causing yellow leaves. Change your peace lily soil mix for something that drains well but still holds a bit of moisture.

Fungus gnats can be controlled using sticky traps. Make sure that the soil drains well to deter them from laying eggs. For pests like mealybugs, use neem oil or insecticidal soap and prune off any moldy or yellow foliage.

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How to Fix Yellow Leaves on a Peace Lily Plant

Prevention is always the best fix for yellow leaves on a peace lily plant. This relies on providing the peace lily with its ideal growing conditions. Create a warm, humid environment with the correct sunlight levels to replicate the jungle floor.

Watering your peace lily properly is the best way to prevent yellow leaves. I always aim to water the plant about once per week if the top inch or two of soil feels dry using water that has been distilled or filtered to prevent chemicals from building up in the soil.

It’s also essential to have the appropriate soil for your peace lily. Use a well-draining mix that can still hold a bit of water. An ideal composition is a 2:2:1 mix of houseplant compost, sand, and perlite. Use a diluted fertilizer once every six to eight weeks to provide your peace lily with plenty of nutrients.

Cultivate the right growing conditions by giving your peace lily a mix of bright indirect sunlight and partial shade. Maintain the temperature somewhere between 55 and 85ºF and avoid hot or cold drafts. Keep humidity levels at approximately 60% by misting or using a humidifier or pebble tray. Recently propagated peace lilies or repotted peace lily plants can be particularly susceptible to cold drafts or inappropriate temperatures.

If the leaves of your peace lily do turn yellow, investigate other symptoms to determine the exact problem. Brown leaf tips mean that the culprit is usually underwatering or low humidity. Clumps of white speckles in the soil are the main signs of poor water quality.

Once you’ve determined the cause, remove the yellow leaves by snipping them off at the base of the stem. Take the appropriate measures to remedy the issue, and your peace lily will perk back up. It’s worth noting that peace lily plants are considered toxic to both humans and pets, so it’s prudent to wear gloves when handling these plants.

Yellowing Peace Lily Leaves – The Final Word

Peace lilies are gorgeous tropical houseplants that are incredibly low-maintenance. But yellowing leaves can sometimes take the shine off your Spathiphyllum. Yellowing leaves are usually caused by overwatering, underwatering, or natural aging of the foliage. Other causes include poor water quality, low nutrient levels, and inappropriate growing conditions.