Have you grown exotic Lemon Trees expecting to enjoy their citrusy aroma and harvest vitamin-rich produces, only to find their leaves turning yellow?
You should know that your plan has gone awry because yellowing foliage may indicate grave problems with your prized plant.
Although Lemon Trees have few pest and disease problems, you may often witness yellowing leaves.
In general, Lemon Tree leaves mainly turn yellow due to improper watering, drought, lack of nutrition, and pest problems. To treat yellow Lemon Tree leaves, provide balanced fertilizer, adequate watering, and bright sunlight for at least 6 hours daily.
Yellowing may occur any time of the year; thus, it may be wise to keep an eye out for untimely yellowing.
However, do not worry because most yellowing foliage problems can easily be diagnosed and treated.
Read on to find common insights about yellowing leaves and ways to treat them effectively.
Table of Contents Show
Is It Normal for Lemon Leaves to Turn Yellow?
When life gives you lemons, you make lemonade, but when the Lemon Tree gives you yellow leaves, you treat them instantly!
Some instances of chlorosis on the Lemon Tree, especially the Meyer Lemon Tree, are common during dormancy, dry summer spell, and old age.
You would mostly witness bottom leaves turning yellow, a few yellow spots, and leaf dropping caused by excess sunlight or temperature changes.
However, it is rare as a healthy plant is less likely to exhibit yellow leaves.
Therefore, you should know that your Lemon Tree is under stress from improper watering, drastic environmental change, or other external factors such as pests or malnutrition.
Very often, the yellow leaves or chlorosis on a citrus tree is caused by overwatering or a nutrient deficiency.
Citrus plants need a lot of watering, particularly during the warm months, but the subsequent poor drainage and nutrient leaching can cause root damage.
Therefore, the stressed Lemon Tree roots are prone to fungal and bacterial diseases, leading to sickly plants and discolored citrus leaves.
It may be an excellent time to assess your Lemon Tree plant to witness sudden changes, especially in spring or summer.
Why is My Lemon Tree Leaves Turning Yellow? (Causes and Solutions)
There are many reasons for your Lemon Tree leaves to turn yellow, but one.
Research indicates that leaf yellowing or chlorosis indicates decreased chlorophyll content and may occur from many different degradations.
Here are a few common causes and solutions for Lemon Trees turning yellow.
1. Overwatering
Overwatering is often the leading cause of most plant-related problems.
In fact, overwatering is the primary cause of chlorosis in Lemon Tree leaves, where the leaf base will start yellowing and quickly spread throughout the surface.
The Lemon Tree plant thrives in moist soil, where it may require regular watering in warm months, leading to the roots soaking in water.
When the roots are submerged in water, they struggle to pull nutrients from the soil and spread them to the stem and foliage, leading to drying leaves.
Therefore, these plants are primarily grown in warm regions, such as USDA 8 or above, where the soil dries up fairly quickly.
On the other hand, Lemon Trees grown in indoor pots are more likely to face overwatering problems due to waterlogging and soil compaction.
Overwatering, using pots with poor drainage and underneath pots, and slow-draining soil may all lead to fungal diseases.
Solutions
- Cut back on watering immediately, move it to the east or south-facing window, and wait for it to dry out.
- If there is too much mulch, remove it by hand to allow the airflow or aerate the soil using a stick.
- Wait until a few weeks before you start watering.
- Always check whether the top 2 inches of soil has dried out before watering or use a watering scheduling app.
- As a precaution, choose well-draining pots or one with multiple drainage holes.
- Moreover, use well-draining substrate containing compost and horticultural grit or perlite.
2. Severe Drought
Like any other citrus species, the Lemon Tree is known to be drought tolerant, withstanding days of less watering.
However, extended under-watering can have severe side effects, leading to leaf transpiration.
A Lemon Tree facing drought will begin losing a lot of water from its leaves due to transpiration, where the leaves will start looking shriveled.
The shriveled leaves with some yellowing indicate an under-watered plant, where the indoor plant is more likely to face drought as the indoor air is drier.
On the other hand, keeping the plant in a room with an air conditioner or heater may also cause quick evaporation.
Solutions
- Immediately water the pot and move it to a location with ample humidity and indirect sunlight until the plant revives.
- Otherwise, submerge the pot in a container filled with water to moisten the substrate.
- Consider replacing the compact or dry soil with a lighter substrate containing compost and perlite.
- As a precaution, generously water the pot until all the excess runs out from underneath once a week.
- Introduce a large room humidifier to boost the humidity level to 50% or above.
- Mist the leaves regularly in summer to maintain some humidity.
3. Under Fertilization
The Lemon Tree enjoys occasional fertilization, usually balanced and organic plant food in the growing season.
In fact, it is a heavy feeder and relies on regular feeding throughout the summer and spring to produce healthy fruits.
The phosphorus and nitrogen deficiency may cause foliage to droop and turn yellow leaves to green veins.
It is widespread with Lemon Trees growing in pots as they have a limited capacity of soil and lesser nutrient uptake.
Similarly, lacking essential nutrients such as magnesium may also restrict growth. Let’s look at the table below to see how the lack of each nutrient affects plant growth.
| Nutrients | Effect on Leaves |
|---|---|
| Nitrogen | Lower and older leaves turn completely yellow and later turns brown before dropping. |
| Potassium | The margin of leaves turn yellow and then brown looking as if burned. |
| Calcium | New leaves turn yellow leading to blossom end rot with chlorotic spots developing along the margins. |
| Magnesium | Leaf margins of older leaves turn yellow leaving the veins green and shows white to light brown necrotic dots. |
| Iron | Young leaves turn yellow leaving behind green veins, and older leaves nearly whitish with yellow to orange chlorosis. |
Solutions
- Apply balanced citrus fertilizer (6-6-6 or 8-8-8) four times a year.
- Water well before and after applying fertilizer to help spread the plant food.
- For better results, use citrus food such as J R Peters – Jacks Classic and Miracle-Gro Shake ‘N Feed Citrus Plant Food.
- Cut back on fertilizing in fall and winter to avoid overdosing on the plant.
4. Lack of Iron
One essential micronutrient for healthy citrus plants is iron to boost green leaves and stems.
The lack of iron in the soil may quickly show up in the leaves, leading to interveinal chlorosis.
Also known as lime-induced chlorosis, you would mostly witness yellow leaves with a network of dark green veins.
In severe cases, iron deficiency may cause the entire leaf to turn yellow or white with scorched outer layers. Moreover, it will produce smaller fruits of poor quality.
Solutions
- Amend the soil with iron supplements (liquid or chelated) to immediately boost iron contents available to the roots.
- Limit using a fertilizer rich in Phosphorus as it may affect the iron intake by roots.
- Adopt specialized fertilizer rich in micronutrients like iron and magnesium and fertilizer every four weeks in spring and summer.
5. Improper Lighting
Lemon Trees naturally thrive in a tropical climate with full sunlight, requiring similar conditions when grown indoors.
The lack of sunlight may inhibit growth in Lemon Trees, causing failed foliage and fruiting.
If your Lemon Tree is deprived of sunlight, it will become leggy, and the bottom leaves will appear paler and yellowish.
Mainly three factors would affect Lemon Tree leaves.
- Fewer hours of sunlight every day
- Lower lighting intensity
- Unaccustomed to Indoor Climate
All three factors affect the plant’s photosynthesis, leading to sickly yellowish leaves.
Solutions
- Immediately move your plant to the south-facing window with full and high-intensity sunlight.
- Ensure to provide at least 6 hours of full sunlight every day in spring and summer.
- In colder climates, they are best kept 12 to 20 inches from LED grow light with 200 watts for 12-hour each day.
- Do not forget to mist the leaves occasionally and deep water the pot once a week.
- Do not move the outdoor Lemon Tree inside immediately. Instead, introduce them gradually by keeping them indoors for a few hours daily.
6. Low Temperature
Lemon Trees are tropical plants that thrive in warmer climates, where extensive exposure to low temperatures may do irreplaceable damage, including yellowed leaves.
Lemon Trees usually prefer the day temperature between 70 to 100°F and nothing less than 65°F at night, where a temperature as low as 50°F (10°C) would mean it is too cold for the plant.
Those exposed to winter temperatures or frost will go under stress, leading to drooping and yellowing leaves.
You would witness excessive leaf shedding along with yellowing.
Solutions
- Relocate your potted Lemon Tree away from the north-facing window to the south-facing window with full sunlight.
- Increase the duration of direct sunlight to 6 hours or more every day.
- Consider covering it with frost blankets at night for plants in colder climates.
- Relocate your plant under an LED grow light for at least 12 hours to offset the risk of cold stress.
7. Pest Problems
Common pests are significant enemies of houseplants, like the Lemon Tree, which would suck on saps and damage the leaves.
The primary reason is spider mites if you notice small yellow spots on Lemon Tree leaves. These insects thrive in low-humidity areas and are attracted to juicy Lemon Tree leaves.
Similarly, citrus bugs, scales, and aphids commonly infest Lemon Tree leaves, affecting them.
| Pests | Symptoms |
|---|---|
| Red Spider Mites | Entire leaves get covered in webs of spiders and pale shiny yellow marks on the top of the leaves and eventually turn brown. |
| Aphids | Leaves turn yellow and later brown from top to bottom with honeydew that promotes sooty mold on foliage and fruit. |
| Scale | It excretes honeydew which accumulates on leaves and sucks saps out of leaves, leading to dried and yellow leaves. |
| Citrus Bugs | They are mostly attracted to new growth, hampering plant development and leaf color. |
Solutions
- Start with clipping off heavily infested leaves and fruits.
- Immediately wash the plant with mild soapy water or horticultural oil to remove pests.
- Alternatively, rubbing insecticidal soap or neem oil on the infected parts will effectively remove the pests.
- Apply citrus bug spray to remove young or mature citrus bugs from the plant.
- As a last resort, using Pyrething or imidacloprid will also help remove and prevent pest infestations.
Related Article: How to Identify Insect Eggs on Leaves and Treat Pest Infestation?
8. Fungal and Bacterial Diseases
The Lemon Tree is prone to many horticultural diseases, which may cause a sickly-looking plant.
Bacterial and fungal infections are the primary culprits for discolored leaves on the Lemon Tree.
Here are some common bacterial and fungal diseases that may infect the Lemon Tree.
| Fungal and Bacterial Diseases | Symptoms |
|---|---|
| Leaf Rust (Pucciniastrum hydrangea) | Appearance of orange pustules on the bottom of the leaves followed by yellow spots on the upper surface. |
| Citrus Canker | It causes yellow halo-like lesions on leaves and fruits, including leaf loss. |
| Powdery Mildew (Erysiphe polygoni) | White cotton-like growth appears on the bottom of the leaves and yellow spots develop on the surface. |
| Bacterial Leaf Spot (Xanthomonas campestris) | Leaf develop brown spots that have yellow edges. |
| Greasy Spot Fungus | A fungal disease produces oily blisters that look yellow-brown. |
| Sooty Mold Fungus | It is common in the lemon trees after pest infestation, like aphids, which lead to yellow or dark leaves. |
| Botrytis Rot | Infects and kill young lemon shoots and new produced fruits |
Solutions
- Start removing the infected leaves by trimming them with a pruning shear and immediately dispose of them.
- Applying neem oil on the infected parts will help remove bacteria. Ensure to rub the solution on both top and undersides of the leaves.
- Applying liquid copper fungicide twice in the growing season will help remove and prevent greasy spot fungus and other diseases.
- Otherwise, you can apply copper-based insecticides twice in the growing season to prevent bacterial infections.
Although the rare, potted Lemon Tree may be infected with Armillaria root rot, a fungal rot caused by mycelium found in the soil, where you will mostly witness wilted, limp foliage with yellowing needles.
However, there is no cure, so you must remove infected parts and maintain good sanitation.
Should I Cut the Yellow Leaves Off the Lemon Tree?
The best option may be to trim the yellow Lemon Tree leaves that look unappealing.
In fact, you can remove the entirely yellowed leaves to help them from spreading further and redirect the energy towards healthy growth.
However, not all yellowing leaves may require trimming, especially those with yellow tips and bases.
Ideally, prune Lemon Tree leaves in late winter or early spring but avoid in summer when the plant is fruiting.
Ensure to use a sharp pruning shear or scissor and sterilize it with isopropyl alcohol before and after use.
Make a sharp cut at the base of the stalk that connects yellow leaves and stems.
You may be interested in reading about germinating Lemon seeds.
How to Prevent Lemon Leaves from Turning Yellow
You can prevent your Lemon Tree from exhibiting yellowed leaves most of the time by maintaining sanitation and an ideal growing environment.
Here are some proven tips to prevent Lemon Tree leaves from turning yellow.
- Provide at least 6 hours of direct sunlight every day in spring and summer by keeping your plant in the south-facing window.
- Water the plant once every week in spring and summer but cut back to two weeks in fall and winter.
- Ensure a humidity level of 50% by keeping it along with other houseplants or room humidifiers.
- Maintain the temperature range between 70 to 90°F for the healthy growth of Lemon Tree.
- Apply balanced fertilizer rich in micronutrients like magnesium and iron every four weeks in spring and summer.
- Always use rich, well-draining loamy substrate without heavy clay as the potting soil and maintain the soil pH around 6.5.
- Prune the plant in early spring and before winter to remove bushier foliage and improve airflow.
- Remember to repot your Lemon Tree to a larger pot every 3 to 4 years.
Read more about simple steps to repot a Lemon Tree
Conclusion
Lemon Trees are very low-maintenance houseplants that would thrive in the average home environment.
However, ensure an ideal growing condition to offset the risk of stress and bacterial or fungal diseases.
Yellowing leaves can easily be avoided by correcting the growing environment and applying immediate treatment.
Follow this guide to find ways to treat yellowing Lemon Tree leaves and proven tips to prevent it.
Related Article: Caring for a Lime Tree in a Pot
