Why Are My Plant Leaves Turning Yellow? 10 Causes and Solutions

Understanding Why Leaves Turn Yellow

Before diving into specific causes, it helps to understand what happens when leaves turn yellow. The green color in leaves comes from chlorophyll, the pigment responsible for photosynthesis. When a plant is stressed or unable to maintain healthy chlorophyll production, the green color fades, revealing the underlying yellow pigments (carotenoids) that were always present but masked by the green.

This process, called chlorosis, can happen for many reasons. Sometimes the plant is redirecting resources from older leaves to newer growth. Other times, environmental stress or care issues are preventing the plant from producing enough chlorophyll. The pattern, location, and speed of yellowing can all provide clues about the underlying cause.

1. Overwatering: The Most Common Culprit

Overwatering is the number one cause of yellow leaves and the most common mistake new plant owners make. When soil stays constantly wet, roots cannot access oxygen and begin to suffocate. Damaged roots cannot absorb nutrients or water properly, leading to yellowing leaves even though the soil is wet. In severe cases, overwatering leads to root rot, which can kill the plant.

How to Identify Overwatering

Yellow leaves from overwatering typically start on the lower, older leaves first and progress upward. The leaves often feel soft and limp rather than dry and crispy. You may notice that the soil stays wet for extended periods between waterings, there may be a musty smell from the soil, and the pot may feel heavy. Other signs include fungus gnats flying around the soil (they love moist conditions) and possible mold on the soil surface.

How to Fix Overwatering

First, allow the soil to dry out before watering again. Depending on the severity, you may need to repot the plant into fresh, dry soil. Check the roots when repotting - healthy roots are white or tan and firm, while rotted roots are brown, black, or mushy. Trim away any rotted roots with clean scissors. Going forward, water only when the top 1-2 inches of soil are dry, and ensure your pot has adequate drainage holes. For more detailed guidance, see our complete watering guide.

2. Underwatering: Drought Stress

While less common than overwatering, underwatering can also cause yellow leaves. When a plant does not receive enough water, it cannot transport nutrients from the soil to its leaves, leading to nutrient deficiency symptoms including yellowing. Severely underwatered plants may also drop leaves to reduce their water needs.

How to Identify Underwatering

Yellow leaves from underwatering are typically dry and crispy rather than soft. The leaves may curl or fold inward to reduce surface area and water loss. The soil will be very dry and may have pulled away from the edges of the pot. The plant may appear wilted, with drooping leaves and stems. Unlike overwatering, lower leaves are often dry and crispy brown before they drop.

How to Fix Underwatering

If the soil has become very dry and compact, it may repel water rather than absorb it. In this case, bottom watering is most effective. Place the pot in a container of water and allow it to soak up water from the bottom for 20-30 minutes. You can also try watering in stages, adding a little water, waiting for it to absorb, then adding more. Once rehydrated, establish a more consistent watering schedule. The affected leaves likely will not recover, but new growth should be healthy.

3. Light Issues: Too Much or Too Little

Light is essential for photosynthesis, the process by which plants produce food and chlorophyll. Both insufficient light and excessive direct sunlight can cause yellowing leaves, though the symptoms differ.

Too Little Light

Plants in low light cannot produce enough chlorophyll, leading to pale, yellowing leaves. This yellowing tends to be gradual and uniform across the plant. You may also notice stretched, leggy growth as the plant reaches toward available light, smaller new leaves than normal, and the plant leaning dramatically toward the light source. Lower leaves, which receive the least light, are often affected first.

Too Much Light

Excessive direct sunlight can cause sunburn or photobleaching. This typically appears as yellow or white patches on leaves that receive the most sun exposure. The affected areas may also turn brown and crispy. Plants that have been recently moved to brighter conditions are particularly susceptible as they have not had time to acclimate.

Solutions for Light Issues

For low light issues, move your plant to a brighter location or supplement with grow lights. Most houseplants need at least 4-6 hours of bright, indirect light daily. For sun damage, move the plant away from direct sunlight or filter the light with a sheer curtain. When moving plants to brighter conditions, do so gradually over a week or two to allow them to acclimate. For more information, check out our guide on plant light requirements.

4. Nutrient Deficiency

Plants need various nutrients to produce chlorophyll and maintain healthy green leaves. When key nutrients are lacking, yellowing is often one of the first symptoms. The pattern of yellowing can help identify which nutrient is deficient.

Nitrogen Deficiency

Nitrogen is essential for chlorophyll production. A nitrogen deficiency causes older, lower leaves to turn uniformly yellow while newer leaves remain green. This is because nitrogen is mobile within the plant, so it is redirected from older leaves to support new growth. The entire leaf yellows, not just between the veins.

Iron Deficiency

Iron deficiency, called iron chlorosis, affects new growth first. Young leaves turn yellow while the veins remain green, creating a distinctive pattern called interveinal chlorosis. This often occurs when soil pH is too high, making iron unavailable to the plant even if present in the soil.

Magnesium Deficiency

Magnesium deficiency also causes interveinal chlorosis, but unlike iron deficiency, it affects older leaves first. The leaf tissue between veins turns yellow while the veins stay green. Eventually, the yellow areas may turn brown and die.

Solutions for Nutrient Deficiency

If your plant has not been fertilized in a while, start with a balanced, water-soluble fertilizer during the growing season. For specific deficiencies, you may need targeted supplements. Ensure your soil pH is appropriate for your plant (most houseplants prefer slightly acidic to neutral pH of 6.0-7.0). Sometimes what appears to be a nutrient deficiency is actually a watering issue preventing nutrient uptake, so rule that out first.

5. Temperature Stress

Most houseplants are tropical in origin and prefer consistent temperatures between 60-75 degrees Fahrenheit. Exposure to temperatures outside their comfort zone, especially cold drafts or sudden temperature swings, can cause yellowing and other leaf damage.

Cold Damage

Cold damage often appears as yellowing or browning of leaves, particularly those closest to the cold source. This commonly happens when plants are placed near drafty windows, exterior doors, or air conditioning vents. Leaves may become soft and mushy if frozen, or simply turn yellow and drop. Tropical plants like Fiddle Leaf Figs are particularly sensitive to cold.

Heat Stress

Excessive heat can also cause yellowing, often accompanied by wilting and leaf curl. This is common when plants are placed near heating vents, radiators, or in hot, stuffy rooms. The plant may also dry out more quickly, compounding the problem.

Solutions for Temperature Stress

Move plants away from temperature extremes - at least 3 feet from windows, doors, and vents. During winter, you can use insulation or move plants to warmer areas of your home at night. Avoid placing plants directly in the path of air conditioning or heating airflow. Consistency is key - even temperatures within the acceptable range can cause stress if they fluctuate dramatically.

6. Low Humidity

Many popular houseplants come from humid tropical environments and struggle in the dry air common in most homes, especially during winter when heating further reduces humidity. While low humidity more commonly causes brown, crispy leaf edges, it can also contribute to yellowing, particularly when combined with other stressors.

Signs of Low Humidity

Plants suffering from low humidity often show brown, crispy leaf tips and edges first, which may then progress to yellowing. Leaves may curl or appear dull and lackluster. Some plants may drop leaves to reduce their moisture loss. Spider mites, which thrive in dry conditions, may also become a problem.

Solutions for Low Humidity

The most effective solution is running a humidifier near your plants. You can also group plants together to create a more humid microclimate, place pots on trays filled with pebbles and water (ensuring pots sit above the water), or move humidity-loving plants to naturally humid rooms like bathrooms or kitchens. Regular misting provides only temporary relief and can promote fungal issues if leaves stay wet.

7. Pest Infestations

Many common houseplant pests feed by sucking sap from leaves, which damages plant cells and can cause yellowing, stippling, or mottled discoloration. If you notice yellowing accompanied by visible pests, webbing, sticky residue, or tiny dots on leaves, pests are likely the cause.

Common Pests That Cause Yellowing

Spider mites cause stippled yellow dots on leaves and fine webbing. Aphids cluster on new growth and cause yellowing and distortion. Mealybugs leave white cottony masses and cause yellowing where they feed. Scale insects appear as bumps on stems and leaves and cause yellowing and leaf drop. For a complete guide to identifying and treating these pests, see our common houseplant pests guide.

Solutions for Pest-Related Yellowing

Isolate affected plants immediately to prevent spread. Treat with appropriate methods depending on the pest - insecticidal soap, neem oil, or rubbing alcohol for most common pests. Be persistent with treatments, as most pest life cycles require multiple applications to fully eliminate. Address the underlying cause of yellowing once pests are controlled.

8. Natural Aging

Sometimes yellow leaves are simply a natural part of a plant's life cycle and nothing to worry about. As plants grow, they naturally shed their oldest leaves to redirect energy to new growth. This is particularly common in spring when plants produce lots of new growth, and they may drop older leaves to compensate.

How to Identify Natural Aging

Natural leaf shedding affects only the oldest leaves, typically at the bottom or interior of the plant. It happens gradually, with one or two leaves yellowing at a time rather than many at once. The rest of the plant looks healthy, and new growth continues normally. If only your oldest leaves are occasionally yellowing and dropping while the plant otherwise thrives, this is likely natural and nothing to worry about.

What to Do

Simply remove yellowing leaves to keep the plant looking tidy and to prevent them from dropping and creating mess or attracting pests. There is no need to change your care routine if the plant is otherwise healthy. However, if leaf drop accelerates or affects newer leaves, investigate other potential causes.

9. Transplant Shock

Repotting is stressful for plants, and some yellow leaves following transplanting are normal. The root disturbance can temporarily affect the plant's ability to absorb water and nutrients. Additionally, any root damage during repotting needs time to heal before the plant can function normally again.

Signs of Transplant Shock

Transplant shock typically manifests as wilting, yellowing leaves, or leaf drop within a few days to a couple of weeks after repotting. The plant may also show slowed growth as it focuses energy on root recovery. This is a normal response and usually resolves on its own.

Minimizing and Treating Transplant Shock

To minimize shock, repot in spring when plants are actively growing, choose a pot only slightly larger than the previous one, be gentle with roots, and water thoroughly after repotting. After repotting, keep the plant in moderate light (not direct sun) for a week or two, maintain consistent moisture without overwatering, and avoid fertilizing for several weeks. Most plants recover within 2-4 weeks. For detailed guidance, see our repotting guide.

10. Root Problems

Various root problems can cause yellow leaves because damaged or restricted roots cannot properly absorb water and nutrients. Root rot (usually from overwatering), root bound plants, and physical root damage all fall into this category.

Root Rot

Root rot is a fungal infection that thrives in constantly wet soil. Affected roots turn brown or black and become mushy, losing their ability to function. Symptoms above ground include yellowing leaves (usually lower leaves first), wilting even when soil is wet, and eventual plant death if not addressed. A foul smell from the soil is often present.

Root Bound Plants

When a plant outgrows its pot, roots become crowded and circled, limiting their ability to absorb water and nutrients. Signs include roots growing out of drainage holes, roots circling the soil surface, water running straight through without absorbing, stunted growth, and yellowing leaves despite proper care. The solution is to repot into a larger container.

Solutions for Root Problems

For root rot, remove the plant from its pot, trim away all affected roots with clean scissors, treat remaining roots with fungicide if desired, and repot in fresh soil in a clean pot with good drainage. Adjust watering habits to prevent recurrence. For root bound plants, carefully loosen the root ball, trim circling roots, and repot into a container 1-2 inches larger in diameter.

Quick Diagnosis Guide

Use this quick reference to help diagnose the cause of your plant's yellow leaves: