Why Is My ZZ Plant Turning Yellow?

ZZ plants, also known as Zamioculcas zamiifolia, are a popular houseplant choice because they're low-maintenance and able to thrive in many environments. However, even the most well-cared-for plants experience issues, such as yellowing leaves.

What Causes ZZ Plant Leaves To Turn Yellow

Overwatering

Overwatering turns ZZ plant leaves yellow because it leads to root rot: when roots are consistently exposed to water and can't get enough oxygen. As a result, the roots decay, preventing the plant from absorbing nutrients properly.

Without proper nutrient absorption, the plant can't produce chlorophyll, the compound that makes leaves green, and the leaves turn yellow. Overwatering also makes the leaves soft and mushy, further exacerbating the issue.

Solution

Start by reducing watering frequency and allowing the soil to dry out partially between waterings. If the soil is still wet, consider repotting the plant in fresh, well-draining potting soil to remove any waterlogged soil that could be contributing to the issue.

Additionally, ensure the plant the pot is in has drainage holes, as this also causes water to accumulate in the soil.

Underwatering

Underwatering turns ZZ plant leaves yellow because they may not have enough water to support their growth and nutrient absorption.

As a result, the leaves start to turn yellow and dry out. Additionally, not watering enough causes the plant to become stressed, which can make it more susceptible to pests and disease.

Solution

ZZ plants prefer to dry out partially between waterings, so it's important not to overwater but also not to let the soil dry completely. 

Water the plant when the top inch of soil feels dry. Be sure to water thoroughly to ensure that the water reaches the roots. You can also mist the leaves regularly to increase humidity around the plant, which prevents the leaves from drying out.

Not Enough Sun

Not enough sun turns ZZ plant leaves yellow because the plant may not be receiving enough light to produce chlorophyll. Without enough chlorophyll, the leaves can't absorb sunlight to have the energy needed for healthy growth.

As a result, the plant may break down stored sugars and nutrients to compensate, causing the leaves to turn yellow. Insufficient light weakens the plant's immune system, making it more susceptible to pests and disease.

Solution

ZZ plants prefer bright, indirect light but also tolerate low-light environments. Consider moving the plant to a location with more natural light or supplementing it with artificial light sources, such as grow lights.

Do not place your plant to direct sunlight, as this scorches the leaves.

Nutrient Deficiencies

Nitrogen and iron deficiencies are common causes of yellowing leaves in ZZ plants, as these nutrients are essential for chlorophyll production.

Without enough chlorophyll, the leaves turn yellow and even curl or wilt. 

Solution

Use a fertilizer specifically formulated for indoor plants containing these nutrients.

Follow the package instructions carefully and avoid overfertilizing, which causes its own set of problems.

Pest Infestations

Pests like spider mites, mealybugs, and scale insects feed on the plant and cause the leaves to turn yellow and eventually drop off.

Some pests also transmit diseases to the plant, weakening its overall health.

Solution

Start by inspecting the plant closely for any signs of insects or mites, such as webbing, sticky residue, or small bumps on the leaves or stems.

Once identified, use an appropriate treatment method, such as insecticidal soap, neem oil, or horticultural oil. Quarantine the plant to prevent the pests from spreading to other plants.

Bacterial Or Fungal Infection

Bacterial or fungal infections turn ZZ plant leaves yellow because they damage the plant's cells and tissues, preventing the proper absorption and distribution of nutrients. The leaves may become yellow as the disease progresses and develop spots or lesions.

Additionally, the plant may start to wilt or show other signs of stress, such as stunted growth or leaf drop. Some infections produce toxins or other chemicals that harm the plant's health.

Solution

Prune any affected parts of the plant and discard them in the trash to prevent the infection from spreading. You can then treat the plant with a fungicide or bactericide.

Frequently Asked Questions

Will yellow ZZ plant leaves turn green again?

If your ZZ plant's leaves go yellow, they may not turn green again until the underlying issue is addressed. If the yellowing is caused by irreversible damage or disease, it's best to cut off the yellow leaves to prevent the spread of infection. Make clean cuts close to the stem with clean, sharp tools when cutting off the leaves.

What will happen to my ZZ plant if I cut off all the yellow leaves?

Cutting off all the yellow leaves from your ZZ plant prevents the spread of infection or disease and promotes new growth. However, if you prune more than one-third of the plant at a time it could cause additional stress and take longer for the plant to recover and produce new growth.

What is the best way to care for my ZZ plant?

ZZ plants are low maintenance and thrive with little water and care.

During the growing season, use a water-soluble fertilizer formulated for indoor plants to provide the necessary nutrients. Monitor the plant closely for signs of droop, stress, or other issues, and address them promptly by adjusting the watering schedule or light conditions.

ZZ plant care is important to prevent yellowing leaves and other issues. A common reason for yellow ZZ plant leaves is excess water, which leads to rot and damages the plant's roots.

To care for your ZZ plant, use well-draining potting soil with perlite or other materials that promote drainage and airflow. Water the plant sparingly and let the soil dry out between waterings, especially during the dormant period. When repotting, use fresh soil and consider dividing the plant's rhizomes if it's root-bound. ZZ plants prefer bright indirect light and tolerate low-light conditions but avoid direct sun, which can cause sunburn.