What Causes Cannabis Leaves to Curl

One involving the major problems the fact that most people experience of cannabis plants is clawing or perhaps curling of the finds. Although the curling along involving cannabis leaves is definitely a good common phenomenon, the idea is usually challenging to diagnose, especially for new stating. When you are a good knowledgeable grower, you can certainly correctly diagnose the reason for the cannabis leaves styling and rectify the problem.

Growing cannabis may look really easy, however, just as other plants, issues may well arise that can impede it has the growth. As the cannabis plants start rising and developing, they will also include leaves and grow in prominence. On the other hand, when leaves commence styling down or upwards, in that case it is a sign the fact that something is wrong with your cannabis plants. Whether you are some sort of starter or an professional grower, you have to diagnose typically the problem causing your cannabis leaves to snuggle together with fix the issue.

Cannabis plants usually deliver signals to show anyone that all is not effectively. If you notice the particular leaves curling down or clawing, then there is usually a good problem with your plants.

The following symptoms are for when your cannabis leaves are “clawing” or curling up or curling down. Sometimes known as “The Claw”. I’ll give a short explanation with pictures of each problem, plus links to the solutions! Fix this common (but hard to diagnose) marijuana problem today!

Nitrogen Toxicity

A Nitrogen toxicity is the result of the plant getting too much Nitrogen (usually from too high levels of nutrients overall, or by using a Vegetative nutrient in the flowering stage). It causes dark green leaves and curled tips (“the claw”).
One of the main symptoms of a Nitrogen toxicity is curled tips (“the claw”)
A plant with a Nitrogen toxicity tends to be dark green all over.

what causes cannabis leaves to curl

Wind Burn

Caused by too much wind. You’ll notice that the leaves further from the fan don’t have symptoms.

what causes cannabis leaves to curl

Bad Soil / Overwatering / Underwatering

You can help prevent over and under-watering your cannabis plants by always starting with good soil or coco coir.

Bad Soil

Bad soil is usually thick and muddy. Plants in poor soil will droop (often with unhappy curly leaves) no matter your watering practices.

Avoid thick soil that stays wet for a long time and doesn’t drain well.


Overwatering makes leaves fat with water, and they tend to curl down and droop.
Overwatering (especially when combined with heat) can also cause leaves to curl up.


Underwatering causes symptoms that often look like overwatering, but you’ll know it’s underwatering if the plants perk up each time after you water them.

Root Problems

Although often caused by overwatering, once the roots are sick you’ll see symptoms for a little while even after you start watering your plants properly.
Unhealthy roots can cause all sorts of problems including curling and clawing!

Unhealthy Roots in Soil/Coco

This plant’s roots were damaged from being overwatered and too hot for several days. As a result, the leaves took on a strange, blistery appearance.
This plant suffered from heat combined with overwatering for several days. This damaged the roots and gave it this odd leaf curling.

Root Rot

Root rot is something marijuana hydroponic growers can suffer from if pathogens attack the roots. It is often triggered by heat and/or lack of bubbles near the roots.
Root rot can cause curling leaves and brown patches as well as sometimes other nutrient deficiencies.


If a plant stays in the same container for too long, the roots will eventually start wrapping around the edges of the pot. This is known as being “rootbound” and causes symptoms similar to other root problems.
A rootbound plant has been in the same container for too long. Roots wrap around the edges and “choke” the plant.
Rootbound plants often droop, appear yellow, get nutrient deficiencies, and stay small. Even if you’re caring for them perfectly!
If you see tons of white roots when transplanted, that means the plant was in that container too long.
When this happens, the main solution is to transplant the plant into a bigger container. Another solution is to grow in fabric pots or air pots. These types of pots let air in from the sides, killing the circling roots (“air-pruning” them) and prevents the plant from getting rootbound for months.
To help a rootbound plant, transplant to a bigger container with fresh potting mix.
Or start with air pots or fabric pots in order to prevent plants from getting rootbound at all.

Heat Stress

If plants are experiencing a lot of heat, it can make leaves droop and/or curl. Some strains can handle a lot of heat, while other strains tend to droop when it gets warm.
Heat can cause leaves to curl up.

Light Burn

Plants can get light burn (sort of like a sunburn) even if the temperature is completely under control. The symptoms are usually concentrated close to the grow lights. Sometimes this can cause leaves to claw and curl downwards.
Light burn can cause the leaves closest to the light to turn yellow.

Bugs & Pests

Often a bug infestation caused general plant unhappiness, but these are some of the most likely to cause curling or clawing leaves.

Broad Mites

Usually, you can’t see broad mites because they live inside the plant. The main symptom of an infestation is strange leaf curling that is specific to this pest, as well as “wet” looking leaves.

Hemp Russet Mites

Hemp russet mites can also cause drooping and other strange symptoms, but the bugs are so small many growers don’t realize what they’re dealing with.
Hemp russet mites cause drooping and yellow mold-like growth on the tops of plants.
A closeup of the hemp russet mites.

Fungus Gnats

Fungus gnats look like tiny flies buzzing around your topsoil. Although a few fungus gnats won’t really hurt your plants, a big infestation can damage the roots, causing symptoms similar to other types of root problems.

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