Basil (Ocimum basilicum) is a versatile herb commonly used in cooking. It has a strong, pungent flavor and is often used to flavor dishes.
While Basil is generally easy to grow, sometimes the leaves can turn yellow. This can be due to several factors, including disease, pests, or poor growing conditions.
If your Basil leaves turn yellow, here are 10 possible causes and solutions.
What Causes Basil Leaves to Turn Yellow and How To Fix It
Basil is a popular herb used in many cuisines around the world. It’s also easy to grow indoors on a windowsill or outdoors in a garden.
Basil leaves are usually green, but if they turn yellow, it can be due to several reasons.
Here are some common causes of yellowing basil leaves and what you can do about them:
1. Too Much Water
Overwatering Basil plants is a common problem, as the leaves will begin to turn yellow and fall off.
This problem is typically caused by too much water in the soil, which can drown the roots and prevent the plant from getting the oxygen it needs.
If your Basil plant is wilting and the leaves turn yellow, check the soil to see if it’s too wet.
The soil should be moist but not soggy.
How To Fix It
If your Basil plant is wilting and the leaves turn yellow, it’s likely because it is getting too much water.
You’ll need to let the soil dry out completely before watering again to fix this problem.
You can also try using a well-draining potting mix to help prevent overwatering in the future.
Basil plants need to be watered regularly, but you should allow the soil to dry out between waterings.
If the soil is too wet, try increasing the time between waterings or choose a pot with drainage holes to help improve drainage.
2. Not Enough Water
Basil leaves can turn yellow for several reasons, but one of the most common causes is lack of water.
When Basil plants don’t get enough water, their leaves will turn yellow and eventually brown and wilt.
Basil is a very sensitive plant; even a little bit of drought can cause its leaves to turn yellow.
Basil needs to be watered regularly, especially during hot weather.
How To Fix It
The good news is that you can easily prevent this by carefully watering your Basil plant regularly and deeply.
If you notice the leaves turning yellow, increase the frequency and amount of water you’re giving the plant.
Basil likes to be kept moist, so ensure the soil is never allowed to dry out completely.
They must be watered at least once a week and more often during hot weather.
3. Lack of Light
Basil is a sun-loving plant that needs at least 6 hours of sunlight per day to thrive.
If Basil plants don’t get enough light, their leaves will turn yellow.
This is because the plant cannot produce enough chlorophyll, which is responsible for giving Basil its green color.
How To Fix It
To fix this problem, move your Basil plant to a brighter location.
If you’re growing Basil indoors, place it near a south-facing window where it will get the most sunlight.
Basil plants need at least 6 hours of sunlight per day, so ensure the plant is getting enough light.
However, too much direct sunlight can also cause Basil leaves to turn yellow.
4. Too Much Light
While Basil needs a lot of light to grow, too much sunlight can harm the plant.
If Basil plants are exposed to too much direct sunlight, their leaves will turn yellow.
This is because the plant is producing too much chlorophyll in an attempt to protect itself from the sun.
How To Fix It
If your Basil plant is getting too much sunlight, move it to a shadier location.
If you’re growing Basil indoors, place it near a north-facing window where it will get indirect sunlight.
Basil plants need at least 6 hours of sunlight per day, so ensure the plant isn’t getting too much or too little light.
5. Nutrient Deficiencies
Basil plants can also suffer from nutrient deficiencies, which can cause their leaves to turn yellow.
Basil’s most common nutrient deficiency is nitrogen, but the plant can also lack other essential nutrients like phosphorus and potassium.
Several factors, including poor soil quality, incorrect fertilizer ratios, and inadequate watering, can cause a nutrient deficiency.
How To Fix It
If you suspect your Basil plant is suffering from a nutrient deficiency, the best action is to get a soil test. This will help you determine which nutrients are lacking and how to amend the soil best.
You can also try using a fertilizer high in nitrogen, phosphorus, and potassium to help correct the nutrient deficiency.
Basil plants must be fertilized every 2-4 weeks during the growing season.
6. Overfertilization
While Basil plants need to be fertilized regularly, it’s important not to overdo it.
Overfertilizing Basil plants can cause their leaves to turn yellow or brown. This is because the plant is getting too much nitrogen, which causes the leaves to turn yellow.
It can also cause the plant’s roots to burn, leading to Basil leaves turning brown and wilting.
How To Fix It
If you think your Basil plant has been overfertilized, flush the soil with water to remove any excess fertilizer.
You can also try moving the plant to a new pot with fresh, unfertilized soil.
Basil plants should be fertilized every 2-4 weeks during the growing season.
7. Pest Infestation
Basil plants can also be affected by pests, which can cause their leaves to turn yellow or brown.
The most common pests that affect Basil plants are aphids, whiteflies, and spider mites.
These pests suck the sap from Basil plants, which can weaken the plant and cause its leaves to turn yellow.
Pest infestations can also lead to Basil leaves turning brown and wilting.
How To Fix It
If you think your Basil plant has a pest infestation, the best course of action is to treat the plant with neem oil or an Insecticidal soap.
You can also try to remove the pests by hand. Use a cotton swab or a Q-tip dipped in rubbing alcohol to kill the pests.
You can also try using a strong blast of water from a hose to remove the pests from your Basil plant.
8. Cold Weather
Basil plants are native to tropical climates and can’t tolerate cold weather.
If Basil plants are exposed to temperatures below 50°F, their leaves will turn yellow. This is because the plant is shocked and trying to protect itself from the cold.
Frost can kill Basil plants, so bringing them indoors or covering them up if you live in a cold climate is essential.
How To Fix It
Bring it indoors and place it in a warm, sunny location if your Basil plant is exposed to cold weather.
Cover it with a frost blanket or burlap sack to protect it from the cold if you can’t bring the plant inside.
You should keep basil plants above 50°F at all times.
9. Basil Downy Mildew
Basil downy mildew is a fungal disease that affects Basil plants.
This disease is caused by the fungus Pseudoperonospora cubensis and can cause Basil leaves to turn yellow or brown.
Basil downy mildew thrives in humid conditions and spreads quickly to other Basil plants.
Signs of Basil downy mildew include yellow or brown spots on the leaves, wilting, and leaf drop.
How To Fix It
If your Basil plant has Basil downy mildew, the best action is to remove all affected leaves.
Destroy any infected leaves that you find to prevent the fungal infection from spreading.
You can also try treating the infected plant with a fungicide.
Basil downy mildew is difficult to control, so it’s essential to take preventive measures to avoid it.
10. Potting Soil Issues
Basil plants need well-draining, nutrient-rich soil to thrive.
If Basil plants are grown in potting soil that’s too dense or doesn’t have enough nutrients, their leaves can turn yellow.
The best way to avoid this problem is to use a high-quality potting mix for Basil plants.
You can also add some organic matter to the soil to improve its drainage and nutrient content.
How To Fix It
If your Basil plant is grown in potting soil that’s too dense or doesn’t have enough nutrients, repot the plant in a high-quality potting mix.
You can also add some organic matter, such as compost, to the soil to improve its drainage and nutrient content.
Basil plants need well-draining, nutrient-rich soil to thrive, so provide them with the best growing conditions possible.
11. Overcrowding
Basil plants need room to grow and should be planted in individual pots.
If Basil plants are overcrowded, their leaves can start to turn yellow. This is because plants compete for space, light, and nutrients.
Basil plants that are overcrowded will also produce fewer leaves and flowers.
How To Fix It
If your Basil plants are overcrowded, repot them in individual pots.
Be sure to provide each plant with enough space to grow.
Basil plants need room to breathe and should be planted in separate pots.
12. Transplant Shock
Basil plants can go into shock when they are transplanted. This is a normal reaction and nothing to worry about.
Basil plants need time to adjust to their new environment and usually recover within a few days.
Symptoms of transplant shock include yellow leaves, wilting, and leaf drop.
How To Fix It
If your Basil plant is experiencing transplant shock, give it time to adjust to its new environment.
Basil plants need time to acclimate to their new surroundings and usually recover within a few days.
Be sure to water the plant regularly and keep it in a warm, sunny location.
13. Natural Leaf Yellowing
It’s normal for Basil leaves to turn yellow as they age.
Basil plants always produce new leaves, and the older leaves will eventually turn yellow and die off.
This is a natural process and nothing to worry about.
Basil plants will continue to produce new leaves as long as they are healthy and happy.
How To Fix It
There’s no need to fix yellow Basil leaves due to age.
Just remove the affected leaves and dispose of them.
Basil plants will continue to produce new leaves, so don’t worry about the plant losing its foliage.
Why Are My Basil Leaves Turning Yellow With Brown Spots?
Basil leaves can turn yellow with brown spots due to several different reasons.
Basil downy mildew, nutrient deficiencies, and herbicide damage are common causes of the Basil plant turning yellow with brown spots.
When diagnosing the problem, it’s essential to look for other symptoms that can help narrow down the cause.
- Due to herbicide damage, Basil leaves turning yellow with brown spots will also have a burnt or scorched appearance.
- Basil leaves turning yellow with brown spots due to nutrient deficiencies often have pale green or yellowish-green leaves.
- Basil downy mildew will cause the leaves to turn yellow and brown and have a powdery or fuzzy appearance.
Why Are My Basil Leaves Turning Yellow and Curling?
Basil leaves can turn yellow and curl due to several different reasons.
Basil downy mildew, heat stress, and pest infestations are common causes of yellow Basil leaves and curling.
When diagnosing the problem, it’s essential to look for other symptoms that can help narrow down the cause.
- Basil leaves turning yellow and curling due to downy mildew will also have a powdery or fuzzy appearance.
- Basil plants experiencing heat stress will often have wilted or drooping leaves.
- Basil leaves infested with pests will have small holes or chewed edges.
Why Are My Basil Leaves Turning Yellow With Black Spots?
Basil leaves can turn yellow with black spots due to several different reasons.
Basil is a very sensitive plant; even small environmental changes can cause Basil leaves to turn yellow with black spots.
The most common reason Basil leaves turn yellow with black spots is lack of water.
Basil leaves also will turn yellow if the plant is not getting enough water or it gets too much water.
Overwatering Basil plants can cause the roots to rot, which will cause the leaves to turn yellow and eventually die.
Should I Remove Yellow Leaves From Basil Plant?
If you have a basil plant, you may notice that the leaves turn yellow. While this is a common problem, it can be frustrating to see your plant suffer.
So, should you remove yellow leaves from Basil plants?
The answer is yes and no. If the leaves are only slightly yellow, you can still use them for cooking.
However, if the leaves are very yellow or starting to brown, it is best to remove them. This will help the plant focus its energy on producing healthy new leaves.
If you decide to remove yellow Basil leaves, be sure to do so gently. These leaves are delicate and can easily be damaged.
Use sharp scissors or pruning shears to make clean cuts.
Basil plants are generally very resilient, so don’t be afraid to trim them back.
Final Thoughts
Basil leaves can turn yellow for a variety of reasons. Most often, it’s due to a lack of nutrients or too much water.
Basil plants also need well-draining, nutrient-rich soil to thrive.
If your Basil plant’s leaves turn yellow, try one of the above solutions.
With some care and attention, you can return your Basil plant to its green and healthy self in no time.
