Cilantro (Coriandrum sativum) is an annual herb that brings fragrance and life to your herbal garden. Additionally, it adds that little fresh taste to different dishes. Provided the right growing conditions, these plants can be grown indoors or outdoors. However, growing cilantro can be challenging at certain times. As a result of wrong growing practices and environmental stresses, the cilantro might change the color of its leaves from green to yellow, purple, white, or red. In this post, you’ll discover reasons for cilantro seedlings/plants changing color, turning red, yellow, brown, purple, pink, black, pale, white, and solutions.
The main reasons for cilantro changing color include lack of fertilization or over-fertilization, high exposure to sunlight or grow light, too much or too little water, pests diseases. Besides, if the plant is root-bound, or planted in bad quality soil, it may be a reason for cilantro leaves turning red, brown, yellow, or purple.
The discoloration of cilantro is mostly accompanied by stunted growth, wilting, and other signs of abnormal growth. Read this post till the end to discover what’s wrong with your cilantro.
Top reasons why cilantro leaves change color
You might be concerned if you bring a lush green cilantro plant from a nursery, but then it starts to change color in your home. It might mean that something is wrong with the herb, and you should take some action.
Let’s discuss some of the basic reasons for the changing color of cilantro leaves. Then we will discuss the reasons for the purple, red, yellow, and white color of the cilantro leaves later in the same post.
Overwatering
Just like other herbs, cilantro doesn’t like getting too wet. The normal functioning of the roots gets disturbed as a result of overwatering. The plant struggles to get enough oxygen, which leads to stunted growth, wilting, and changes in coloration.
Excessive moisture in the soil for prolonged periods also promotes fungal growth. Lack of sunlight to help dry the water from the soil and leaves due to overcrowding or lack of light can also lead to this. Also, make sure to have an 8-10 inch (20-25 cm) gap between cilantro plants. What is more, make sure to use well-draining soil for growing cilantro (coriander) and use pots with drainage holes.
If you have overwatered the cilantro and you are sure that the color change of cilantro is due to overwatering, then you can fix it. Do the following:
- Let the plants dry for a few days.
- Slightly loosen the soil to make more space for roots to breathe.
- Avoid repotting cilantro, as it is an annual herb, and the taproot of the cilantro can get easily damaged during repotting. The leaves will return to their previous color within a few days.
- If you need to transfer your plant to a bigger pot, make sure to do it carefully.
Underwatering
All the plants absorb nutrients from the soil in water-soluble form. If you are not providing enough water needed for the proper functioning of cilantro, your herb will show negative symptoms.
In the case of underwatering, the cilantro roots fail to absorb necessary nutrients. As a consequence of underwatering, the plant may wilt or show abnormal growth and change its color. If you have confirmed that the color change of your cilantro is due to underwatering, you can easily fix it by providing enough water. Cilantro leaves mostly turn yellow due to a lack of water.
- Provide some afternoon shade to your plants during high mid-day temperatures.
- Also, make sure that the pot has no water in the saucer. Get rid of any excess water.
- Water with filtered water or tap water left in a bucket/container for at least 12 hours.
- Don’t use high chlorinated or hard water that has been treated with softeners.
Compacted soil
Compacted soil causes several serious problems in cilantro. The changing color of cilantro leaves is also one of these symptoms of compacted soil. In general, the potting mix becomes compacted with time. And it gets the infiltration of water into the soil reduced.
As a result, the root system of the plant suffocates due to a lack of water and oxygen. Also, the plant fails to absorb nutrients from the soil and turns brown, red, or yellow.
- To fix this issue, loosen the top layer of soil not more than 1 to 1.5cm.
- Make sure not to damage the roots closer to the surface. Without any damage being made, the roots will absorb the nutrients by receiving the required oxygen needed for proper functioning.
Soil pH
Different plants grow well in different ranges of pH. Cilantro loves growing in the slightly acidic soil. The soil pH for cilantro should be 6.5 to 6.8. This herb will grow abnormally and change the color of leaves if it is grown in the soil of pH that is very far off the optimal values. However, cilantro plants don’t have strict soil requirements – make sure it’s well-draining and rich in organic matter.
- To fix the soil pH, first, perform a soil test by using a pH kit. If the soil is too acidic, amend it with limestone.
- If the soil is too alkaline (above 7), you can use citric acid mixed with water to increase the soil acidity.
Intensive direct sunlight
If your indoor cilantro is placed under an intensive grow light or is under some sort of stress, its leaves might start turning purple. Similarly, the outdoor plants placed in the sun for prolonged periods of time start to lose the color of leaves during the summer season or develop purple tint. Also, the leaves become light and crispy as a result of too much sunlight.
Follow these tips to bring back the green color of your plants.
- Put the indoor plants on a south-facing windowsill where they can receive 6 to 8 hours of direct sunlight.
- Place cilantro under an LED grow light if you don’t have enough sunlight. However, if you have enough sunlight coming from the window, there is no need to place the plants under grow lights. Using grow lights might be more needed if growing cilantro in winter indoors.
- Avoid placing plants under very intense grow lights. Around 4″ (10 cm) away from plants is a general guideline.
Cilantro (coriander) diseases
Several bacterial and fungal diseases of cilantro are responsible for changing the color of leaves. As a consequence, the plant suffers from stunted growth, and the leaves turn red, yellow, or brown.
Soft rot: It is a bacterial disease of cilantro. The bacteria attacks the soft tissues of the plant and causes the petioles to become mushy and brown. High temperature and humidity levels are responsible for the growth and spread of this disease.
Soft rot is hard to control. You can follow these preventive measures to control the problem in the future.
- Select disease-resistant varieties of cilantro.
- Avoid overcrowding of plants. Allow 8-10″ (20-25 cm) between plants. Cilantro grow in clumps.
- The bacteria enter the plant through cuts. So, avoid damaging the plants.
- Discard all the debris of infected plants to avoid the spread of disease.
Root rot: It is a fungal disease of cilantro. It damages the root of plants. As a result, the roots start to rot and fail to supply essential nutrients. The leaves then turn yellow, brown, purple, or red.
Follow these tips to prevent root rot.
- Use a fungicide to kill the fungal spores.
- Remove and discard the whole plant if the infection is severe.
- Avoid overcrowding of plants.
- Don’t overwater the plants. Use well-draining soil and use pots with drainage holes on the bottom.
Cilantro (coriander) leaves turning purple
Are your cilantro leaves turning purple? As you know, cilantro is an annual herb. It grows for one season, produces flowers and seeds, and dies. If cilantro is exposed to high temperatures/extreme sun for longer periods, it will start bolting and turning purple. Bolting means the upright growth of plants to produce more flowers instead of leaves. High temperature sets premature bolting and leads to the leaves turning purple.
To prevent premature bolting, provide afternoon shade to the plants. However, don’t worry if the plant bolts even after your revival efforts. Let the plant set seeds and sow new seeds to get a steady supply of cilantro throughout the growing season. If you want a continuous supply, sow seeds every 3-4 weeks up to mid-summer (beginning of July or so). And if you have mild fall and winter, you can sow needs seeds again after summer has ended.
Many plants turn purple when exposed to extreme sunlight and stress, in order to protect themselves. Another reason for an early bolting and purple coloration in cilantro is being potted in a very small pot. If your cilantro plant outgrows its pot, it will start stressing due to a lack of space. Make sure to pot cilantro in a pot that’s minimum 10″ (25 cm) wide and 8″ (20 cm) deep.
Cilantro (coriander) leaves turning red
Most gardeners feel concerned when they notice cilantro (coriander) leaves turning red. However, red coloration is not always a bad sign. Cilantro leaves might red due to a pigment named anthocyanin. The plant produces this pigment when they lack phosphorus, an essential element for the healthy growth of plants.
However, phosphorus deficiency doesn’t mean that the soil is lacking this element. Maybe it is present in the soil, but the plant’s roots are not able to absorb it. To check if the redness of leaves is due to phosphorus deficiency, first perform a soil test.
For this, you can use a kit like this one. Never add too much phosphorus-rich fertilizer to the soil before confirming the deficiency. An overdose of phosphorus can be detrimental to your cilantro. If your plant actually needs phosphorus, add bone meal or another herb fertilizer with higher P content.
Another possible reason for cilantro leaves turning red is when it’s about to produce seeds. If you believe it’s too early for your cilantro to start producing seeds (you haven’t had much harvest), that could mean that temperatures are too high. This could result bolting (high temperatures lead to early flower and seed production in cilantro). You might also look into getting seed varieties of cilantro that don’t bolt too quickly.
If you wish to discourage bolting, you can trim the plant – remove stems producing seeds. Sow new seeds if your plant has bolted and leaves are not tasty/good enough to use in the kitchen.
Cilantro (coriander) turning yellow
If your cilantro is turning yellow in places, make sure to check soil drainage. Overwatering can lead to limp and yellowing leaves in cilantro. Another possible cause of yellowing in cilantro is lack of nutrients or the plant being burned by too much fertilizer.
An organic seaweed fertilizer like this one, or another herb fertilizer will be great to supplement your plants if it’s the case. Make sure the plants are not scorched either by allowing afternoon shade. If you are using grow lights for your cilantro, don’t move it too close to the plant. Depending on the grow light strength, you might need to allow 4-8″ (10-20 cm) or so away from the plant.
Cilantro (coriander) leaves turning white
Have you ever experienced leaves of cilantro turning white? If yes, it is a condition called chlorosis when a plant fails to produce enough chlorophyll. It is a sign that the cilantro plant is in distress.
Several factors are responsible for chlorosis in cilantro. But mainly, it is due to insufficient light exposure. The herb can’t perform photosynthesis to produce chlorophyll. As a result, the plant can’t make its food.
The other reason for white spot formation on the cilantro is due to powdery mildew. It is a fungal disease that occurs when plants are overwatered or overcrowded. Mild cases of powdery mildew recover with the improvement of weather and growing conditions. The spray of potassium bicarbonate can be effective for killing the spores of powdery mildew.
Cilantro (coriander) turning brown or black
If your cilantro (coriander) is turning brown or black, it’s likely to be due to overwatering or root problems. Make sure not to water your cilantro before the soil dries out – cilantro needs well-draining soil. You can use a simple moisture meter like this to help with watering. Always have a saucer under the pot, if growing cilantro in pots. Remove excess water from the pot after watering.
Tips to prevent cilantro leaves from changing color
Here are a few tips that will help prevent your cilantro from changing its color. By following these tips, you will increase the chances of growing healthy cilantro plants.
Make sure to plant cilantro in readily-draining soil that’s rich in organic matter. Also, the pots must have drainage holes on the bottom. Keep the pots in a well-ventilated area. Make sure to allow the soil to dry out between waterings. Also, allow 8-10″ (20-25 cm) between seedlings, and at least 6″ (15 cm) between sown seeds. Regularly check your herbs for any infected or damaged growth. Remove the infected plant parts to prevent the spread of diseases.
What is more, make sure to maintain a temperature between 60 to 80 degrees Fahrenheit (15.5-26.6 C) if planting cilantro in a greenhouse. Use a water jet and insecticidal soap for pest infestation on affected cilantro plants.
Conclusion
If your cilantro is changing color, and turning red, yellow, purple or red or another color, it doesn’t necessarily mean that’s something is seriously wrong. Sometimes, the changing color of leaves is perfectly normal. So, don’t panic and follow the care guidelines mentioned in the post. Think about environmental changes, temperatures, sunlight, soil, and other factors to determine the causes of color change.
To discover more useful tips on growing cilantro, see this page.