Growing peppers truly is a science. It can be accomplished with simple means; soil, water and the sun. Or, it can be done in a complex lab with precise nutrients and watering. However, as with anything that is alive, imbalances and stress can cause issues.
With peppers, the plant will give clear signals when something is wrong. One common issue that is found in pepper plants are when the leaves begin curling. This can happen for a few reasons, and this article will discuss what you can do when your pepper leaves are curling.
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Why Are My Pepper Leaves Curling
Of the many potential causes, there are four that are most likely to be causing pepper leaf curl. Each has a slightly different presentation of the problem, so try to diagnose your issue and treat accordingly.
Leaves curling is a sign of stress in your plant, and it can usually be remedied with some simple adjustment to your plant care routine.
One of the worst things you can do to your pepper plants is to keep the soil too moist. Pepper plants prefer soil that is on the dry side, while too much water will lead to many problems.
Overwatering can cause pepper leaves to curl due to the roots’ inability to access enough oxygen and nutrition from the soil. Overwatering will also usually cause yellowing leaves and stunted plant growth.
The solution: Water only when the soil has become mostly dry. You can know that the soil is dry enough to water by feeling the soil just below the surface, or by lifting the pot to feel the plant’s weight. If you allow the plant to dry too much, the leaves will begin to wilt, but will rebound after a watering. You can also try using a cheap water meter from amazon to check soil moisture.
Plant edema is a common cellular disorder caused by irregular water retention. It will appear in peppers as a whitish, crystallized substance underneath the leaves. Extreme edema can cause plant leaves to curl.
The solution: Read our dedicated article on treating plant edema here.
Calcium is a secondary nutrient for pepper plant growth. Among other things, it is used by plants to develop strong cell walls. When not enough calcium is provided, leaves cannot develop properly and will begin to appear curled and bubbly. This is sometimes accompanied by brown spots on the leaves and there may be other signs of nutrient deficiency like yellow leaves.
The solution: Provide calcium to the soil through the use of bone meal or other calcium supplements.
Calcium and magnesium are both secondary nutrients that can be provided to avoid irregular plant development. These are sometimes, but not always included in pre-fertilized soils, so check your soil ingredients!
Many all-purpose fertilizers will also include calcium, but not all. Check your fertilizer to see what nutrients are being provided.
We love Fox Farm fertilizer trio for simple, well-balanced feeding.
Too Much Light
Providing light to your pepper plants is essential. Peppers like full sunlight throughout the season, so if you are planting outdoors, lighting is unlikely the issue.
One potential cause for outdoor light burn is watering in direct sunlight. The beads of water can refract the sunlight and cause burn spots on the leaves. However, these appear as dark burn spots on the leaves rather than curling.
You may see some leaf curling when you first transition your plants outdoors. Be sure you are hardening off your plants properly and gradually acclimating them to direct sunlight.
A more common issue is caused by using indoor grow lights incorrectly. Grow lights can vary widely in brightness and intensity. They are essential if you start your own pepper seeds indoors, but you have to follow the light instructions for how close the lights should be to your plants.
If your plants are too close to the light, you will begin to see the leaves curling up and closing in rebellion from the light. This problem will eventually cause pepper leaves to dry up and fall off, often turning brown and crumbling when squeezed.
The solution: If you think your plants have light burn, adjust your lights a few inches higher. Our grow light needs to be 12-18 inches away from the canopy of leaves.
Also, make sure the lights are set on a timer to be on for 12-16 hours, and off for the rest of the day. Check that the timer is working properly, as 24/7 light is not good! If you’re outdoors, try to water at dawn or dusk to avoid leaf burn.
Uncontrolled insects can be the bane of your garden. They come from seemingly nowhere and can wreak havoc on your plants in a matter of days.
Curling pepper leaves can be a sign of insect damage, though it will typically be focused on individual leaves rather than the whole plant. Curled and bubbled leaves are the leaves that the insects have been eating.
If the entire pepper plant has curled leaves, it is likely one of the other issued mentioned. However, if you notice localized leaf curling, you may have aphids, thrips, spider mites or another insect pest.
Unfortunately, pest removal is more difficult than preventative care. However, you can take some measures to try to alleviate the issue and get rid of most of the insects.
The solution: Hand-pick the affected leaves and burn them if possible. Otherwise, bring them outside and discard because insects spread easily. You can also introduce ladybugs or other helpful insects that feed on the pests and not on your pepper leaves.
As a preventative measure, neem oil is effective – simply work the suggested amount into your soil before transplanting or spray a diluted solution onto the foliage.
After treatment, do not expect the curling leaves to flatten out and look perfectly healthy. Just because the plant doesn’t re-form to look beautiful doesn’t mean the issue hasn’t been resolved.
Expect new leaves to look properly formed and understand that the curling leaves will remain curled. The best way to solve most planting issues is to plan ahead.
Read our full guide to growing peppers here to make sure you’re giving your pepper plants the best chance they have from day 1.
Other Causes Of Pepper Leaves Curling
Though the causes mentioned are the most common, there are many other potential issues that can cause curling leaves. If you are sure that none of the other causes apply or you have tried without success, there are some other, less common causes.
Your plants could be root bound. Learn more about root bound plants in our article here. This issue is caused by plants being kept in containers that are too small. The roots can become entangled, eventually causing distorted leaves.
Your pepper plants could have a bacterial infection, though this is often accompanied by brown, circular spots. This is often caused by using sterilized soil which can attract new colonizers, or by not rotating crops each year.
If you are growing indoors, your plants may suffer from poor pollination, which can cause distorted leaves. Try hand pollinating or shaking the plants after the flowers have opened. This issue is also accompanied by dropped flowers and a lack of pepper pods.
Remember, curling pepper plant leaves are usually nothing to worry too much about! Look at your plants as a whole and try not to get too hung up on a few curled leaves. If your plant looks mostly healthy, then be happy about that. Keep an eye out for more concerning issues like fungal issues and garden pests.
We hope this article helped you diagnose why your pepper plant leaves are curling. Growing peppers can be a challenge, but the reward is always worth the extra effort. Good luck, and let us know if you’ve had success with treating your curling pepper plant leaves!