Why Your Christmas Cactus Is Dropping Leaves—and How to Fix It ASAP

Christmas cactus leaves open up and present beautiful, bright buds around the holidays. These show-stopping blooms will impress guests and family members alike—so it's disheartening when the leaves start to drop.

Don't worry, though—there are ways to remedy this common issue. First, it's important to know why exactly the leaves are falling. We spoke to experts about how to get to the bottom of this dilemma, so that you can keep your Christmas cactus healthy and thriving.

Underwatering

Too little water can lead to leaf drop. “When these plants go without water for an extended period, they rely on the moisture stored in their leaves," says Angelica Elliott, assistant director of public horticulture for Desert Botanical Gardens. "This can cause the leaves to become wrinkled. Once they reach a critical point where their stored water is depleted, they will start shedding."

Instead, let the top inch of soil dry out before watering again. Plant your cactus in a well-draining mix, and check the soil before watering. "Insert your finger a couple of inches into the soil. If it feels dry, then it's time to water," says Elliott.

Overwatering

Conversely, overwatering can also lead to leaf drop. In this case, the roots will begin to rot and die; if they're compromised, then the plant will be unable to absorb water and will drop its leaves. Additionally, rot can ascend the stem, potentially causing the entire plant to decay.

One effective way to avoid overwatering your plants is to invest in a moisture meter, which will help you gauge the remaining water in the soil. “Aim to keep the soil slightly damp, but avoid making it soggy," says Elliott. "Don't worry if your plant begins to rot; you can trim off the healthy sections and re-root them."

Make sure that your pot has drainage holes, which will allow excess water to escape. “Consider using a cactus or succulent mix and adding pumice, leca, or coarse orchid potting mix for better drainage,” she says.

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Pests

When pests feed on the leaves or roots of your plants, they can cause significant damage, leading to leaf drop. Look out for these varieties in particular:

• Mealybugs: These pests feed on both the stems and roots of your Christmas cactus.
• Fungus gnats: Often found on indoor plants, their larvae can munch on the roots within the soil.
• Spider mites and scale insects: Both of these pests target the leaves, feeding on the plant's foliage.

To prevent and catch pests, make sure to examine your plant closely, especially in the creases where segments connect. “If you see pests, move the plant away from any others,” says Sam Niemann, landscape designer and founder of Bleume and Grown by Design. “Treat the cactus with insecticidal soap or neem oil, and repeat as needed. Wipe away residue after treatment, and consider repotting if the soil looks compacted or unhealthy.”

Consider regular baths for your plants. “Spider mites thrive in hot, dusty conditions, so periodically washing your plants will help remove dust from their leaves,” says Elliott.

Sunlight

Plants require a specific amount of light for optimal growth, and the Christmas cactus is no different. “[It] thrives in bright, indirect light; when grown in low-light environments, the Christmas cactus may become stunted or etiolated,” says Elliott. “Insufficient light affects its ability to photosynthesize effectively, leading to a gradual decline, as it can no longer produce food for itself. Consequently, the plant may start to droop and lose its leaves.”

Keeping your plant in a spot with bright, indirect light will prevent this outcome. “An east-facing window works well, and so does a bright room with filtered light,” says Niemann. “Avoid strong, direct sunlight in the middle of the day, since that can scorch the leaves. If the plant lives in a darker corner, add a small grow light during the winter months.”