12 Reasons Your Indoor Citrus Tree is Dropping Leaves

While citrus trees like lemons and limes are fun plants to grow at home, they can be challenging to care for. One of the most common problems citrus trees face is dropping leaves. There are several different causes of leaf drop, including environmental problems, diseases, and natural phenomena. While it would be nice if it was easy to pinpoint the cause of dropped leaves, the truth is there could be a variety of items to blame. Here are 12 of the most common reasons indoor citrus trees drop their leaves.

1. The Temperature

While most varieties of citrus trees are tropical fruits, they can still be negatively impacted by high temperatures. Temperatures over 95°F can stress the plant. Extended high temperatures may cause leaf drop, especially if you under-water.

Low temperatures can also lead your plant to become stressed, which leads to dropped leaves. Sudden shifts in temperature, such as those that come with the first cold fall night, often cause the tree to drop some leaves. While plants can recover from a bit of cold, you should avoid freezing temperatures.

Another thing to consider about temperature is the change between day and night. Citrus trees prefer nighttime temperatures that are 5-10°F cooler than they are during the day.

2. Humidity

Citrus trees prefer moderate to high humidity. Dry air can stress plants and lead to yellowing and dropping leaves.

It’s especially important to pay attention to the humidity during winter. Heaters often dry out the air, so you may need to supply your plants with supplemental humidity. Use a humidifier or mist your plants with water.

3. Drafts and Poor Ventilation

You should keep your citrus tree somewhere where it experiences a near-constant temperature where possible.

While slow temperature changes generally aren’t a concern, sharp changes can stress the plant. For example, if you have your plant near a cold draft, it will be shocked each time it is hit with cold air. The same holds true for warm drafts.

Keep your citrus tree away from heating and air conditioning vents as well as poorly insulated windows and doors.

Proper ventilation is also key to a healthy plant. Airflow helps prevent issues with diseases.

4. Over-Watering

While citrus trees like lemons and limes like a lot of moisture, you should allow the soil to dry out in between waterings. It’s best to use deep, infrequent waterings rather than shallow, frequent waterings.

If the soil is constantly moist, your plants struggle to take up nutrients and air. Therefore, they become stressed. This results in leaves that turn yellow and eventually drop.

Overwatering can also lead to a fungal disease known as root rot. This causes the roots to become mushy and rotten, which can lead to several other problems, including leaf drop.

5. Under-Watering

Your plants will also suffer if you don’t apply enough water. Citrus trees are thirsty plants and will struggle if the soil completely dries out.

Remember that numerous factors impact how often you’ll need to water. Citrus trees require more water in hot, bright summers than they will during the darker days of winter. Larger trees will also require more water than smaller trees.

Also, it’s important to remember that citrus trees thrive with deep waterings. When you water, you want moisture to reach all of the plant’s roots. This means watering until you see water flow out of the pot’s drainage holes.

6. The Seasons

Citrus trees like lemons, limes, oranges, and kumquats don’t have true dormancy periods. This means that they don’t stop growing like fruit trees such as apples and pears (this is also a good time to consider pruning your citrus tree).

With that said, citrus trees can still experience leaf drop in winter. If temperatures are too cool for vegetative growth, your plant will lose leaves without growing any new leaves. This can make leaf drop more noticeable.

When temperatures warm back up in the spring, your plant should resume growth. Before long, it will replace the leaves it lost during the winter.

7. Blossom and/or Fruit Formation

When trees form blossoms and set fruit, they naturally drop some of their leaves. If you notice your tree is losing a few leaves during this time, you don’t need to worry.

Forming flowers and fruit takes a lot of energy. Therefore, trees may not be able to spend all the energy they need to keep their leaves.

As leaves fall, the tree will produce new leaves to replace the lost leaves. If you notice your tree is dropping lots of leaves at once, another cause is likely to blame.

8. Light Conditions

Citrus trees typically thrive in bright, direct sun. During the summer months, they need at least 8 hours of bright sun each day. If these needs aren’t met, they may drop their leaves.

Even if you are providing enough hours of sun, the light might not be bright enough. Citrus trees need direct, bright, sun. If your plant isn’t in direct sun, you’ll need to use a high-powered grow light.

During the winter, the plant’s light needs change a bit. If the roots are at a cooler temperature, they will not require as much sun. Exposing the plants to the direct sun when the soil temperature is 60°F or below can lead to a condition known as winter leaf drop.

9. A Nutrient Deficiency

Like all plants, citrus trees need nutrients to survive. Unlike many other houseplants, citrus trees are heavy feeders. Therefore, they’ll need regular application of fertilizer.

A lack of nitrogen, magnesium, and other nutrients often leads to yellowing leaves that eventually fall off. To prevent nutrient deficiencies, fertilize monthly with a product designed for citrus trees.

Since trees planted in potting soil will not be able to access micronutrients found in soil, you’ll need to help your tree meet these needs. Organic fertilizers like azomite and kelp meal contain these trace minerals.

While proper nutrition is key to a healthy plant, remember that you can over-fertilize. If you apply an overly strong fertilizer, you will shock your plant. This will often result in leaf drop.

10. The Age of the Plant

Some leaf drop is natural. When a citrus tree reaches three or four years old, you’ll start to notice leaves drop one by one.

While a few leaves dropping isn’t anything to worry about, you should take a closer look if you notice your plant is losing lots of leaves at once.

11. Fungal or Bacterial Infections

Lemon trees are susceptible to several types of diseases.

Root rot is the common name for infections caused by the fungus Phytophthora. This disease is more common when plants are overwatered.

To prevent root rot, wait to water until the top inch of soil is dry. Additionally, make sure your pot has proper drainage holes. If you have a dish under your pot, make sure to empty any standing water.

Another disease that impacts citrus trees is greasy spot. This fungus leads to dark leaf lesions. Eventually, the leaves drop.

Fungal diseases typically thrive in dark, moist conditions. To help prevent fungal disease, avoid overwatering, and provide adequate airflow.

If you are constantly having problems with foliar diseases, you can use a copper fungicide to treat the issue.

Sooty mold is one more common fungal disease that impacts citrus trees. This disease only impacts trees after sucking insects like aphids or scale.

These insects release a sticky substance called honeydew. Once this honeydew covers the leaves, sooty mold may form. While this mold doesn’t infect the plant itself, it can lead to leaf drop.

12. Repotting

Even if you try your best to be careful, repotting is still stressful for plants. It’s not uncommon for citrus trees to lose some leaves after you repot them.

After you repot your citrus tree, it may look stressed for a few days. However, as long as you provide it with the right environment and the proper amount of water, it will likely recover.

If you want to avoid stress, repot your plant in the winter, when its growth is slowed.

In addition, it’s important to consider the most appropriate potting soil for citrus trees. Citrus trees prefer a well-draining potting soil that provides a mix of aeration and water-holding capacities. For more, see our essential guide to citrus tree soil here. 

Tips, Cures, and Remedies for Citrus Trees Dropping Leaves

If you notice your plant is dropping leaves, refer to the list above. By taking into consideration the time of year, watering schedule, and other factors, you can determine the likely cause of leaf drop.

If you can pin down the reason why your tree is dropping leaves, you can work to reverse the problem. For example, if you realize you are watering your tree too often, decrease the amount you water.

When you’re unsure what’s causing your tree to drop leaves, take a look at the environment. By ensuring you’re providing your plant with what it needs, you’ll lessen the chance it will drop its leaves.

Here are some basic care tips when it comes to keeping your citrus tree happy.

Environment

Keep temperatures between 65-80°F. Lower temperatures by 5-10°F at night.

Citrus trees prefer medium to high humidity, so make sure to add moisture if your air is very dry.

To keep your plants healthy, make sure they receive at least eight hours of bright, direct light during the summer. It is fine to move your plant outside if it is warm enough.

During winter, plants don’t require as much light. However, they should not be kept in complete darkness nor shade.

Watering and Fertilizing

Citrus trees aren’t drought-tolerant, but they also struggle with constant moisture.

A good practice is to allow the soil to dry out an inch or two before watering again. Make sure you use a well-draining potting mix and a planter with drainage holes to allow excess water to escape.

Disease Prevention

Good airflow will help prevent fungal diseases. You can use a fan to help circulate stagnant air.

One key point to preventing fungal diseases is avoiding overwatering.

Another part of preventing disease is avoiding introducing diseases. Always check new plants for signs of disease, and don’t bring sick plants inside.

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Wrapping Up

Now that you know some of the common causes of indoor citrus trees dropping leaves, it’s time to work to determine the cause of your tree’s problems. Once you identify the cause, work to remedy it.

If you’re not sure of the cause of leaf drop, follow the tips for citrus tree care. After a few months of proper care, your plant should return to a healthy state.

Further reading: the best types of indoor citrus trees to grow at home.