How to Fix Marijuana Leaves Curling Up

When cultivating marijuana, the process may seem easy and straightforward. However, when disastrous problems will arise, it could potentially impede the proper growth of the plants.

A few of the biggest issues in cultivating marijuana especially among amateur growers are marijuana leaves curling up or occasionally call it as clawing. Although this issue might be commonly seen on plants, including marijuana, the diagnosis can be hard to come up with. When the leaves start to show signs of curling up, your plants are trying to send a call for help and requires fixing.

There numerous reasons that could potentially be the cause of marijuana leaves curling up, including too much provision of water and fertilizer, heat stress, cold temperatures, and natural genetics. Hence, in this article, we will take a further investigation of the causes of marijuana leaves curling up and how to fix it while preventing your final crops from getting damage entirely.

The Claw

The Claw is the most famous term for marijuana leaves curling up or down. When this happens, then immediate action should be taken accordingly and apply proper treatment to the plants, so that it will not hamper its development or end up dying.

Marijuana Leaves Curling Up: Reason and Treatment

Excessive Fertilizer

Too much of something is bad. This statement can be applied to marijuana plants as well. When providing fertilizers to them seems a good help to encourage development and growth, an excessive amount of it can result in disastrous consequences on the plants, particularly when there is an overwhelming amount of nitrogen, minerals, or vitamins. It could provoke marijuana leaves curling up or down and the tips will tend to scorch.

When overfeeding the marijuana plants during the vegetation stage with fertilizers that are enriched with high doses of nitrogen, the tendency would result in marijuana leaves curling up. Additionally, during the flowering stage, when there are overwhelming amounts of potassium and phosphorus, the marijuana leaves can burn its tips.

How to Fix This?

The only way to fix this issue of marijuana leaves curling up due to overfeeding, is to create a feeding chart that allows you to monitor and control everything you provide to the marijuana plants. Typically, the feeding comes along when buying fertilizers and some can be downloaded on the brand’s site.

In simple terms, to fix marijuana leaves curling up or to prevent it from transpiring, it is always better to start with slow interval and low dosage. As time goes, when there no signs of marijuana leaves curling up, you can gradually increase the amount of fertilizer and monitor how your crops react to the dosage. When attempting to dive in at utmost nutrient quantity, there is a high possibility of curling up and eventually damaging the whole crop.

Proper dosage of fertilizer must be compatible with the pH level of soil, instead of doing trial and error attempts. On average, the correct pH level is approximately 5.8 pH up to 6.0 pH. The former is ideal for coco coir or hydroponic growing while the latter is favorable for soil cultivation.

Too Much Water

Opposing the common belief that when watering marijuana plants or any type of plants can retain its healthy and thriving condition, however, this is not completely credible. While water is necessary to plants, too much of it can cause the plants to drown their roots.

Additionally, the essential microbes will be rinsed out from the medium of the plant and the excess eater will trigger the development of fungus and algae. When overwatering continues it could lead to the attraction of Pythium, a parasite that causes rotting of the roots. As soon as this happens, you can expect that it will end up marijuana leaves curling up.

How to Fix This?

These microorganisms are not present within the medium of the crops without invitation, hence, to fix this issue of marijuana leaves curling up, it requires to keep them out of the area. As a newbie or veteran cultivator, it is a vital part of the cultivation process to constantly maintain a beneficial cycle of wet and dry.

If identifying when to water plants can be a difficult task, then better consider having a moisture meter. This allows anyone to gets an accurate measurement of moisture on the marijuana plants while utilizing it, never skip to monitor the condition of the plant at a post-watering state. When the marijuana leaves curling up are gradually showing, better lessen the water quantity provided and schedule a longer period of intervals when watering the marijuana plants. Nonetheless, when you can still see signs of marijuana leaves curling up, check out the roots to see if the pythium have penetrated it and kill them immediately.

Heat Stress

One of the causes of marijuana leaves curling up is due to too much heat or as a popularly known as Heat Stress. The common sign of heat stress is when marijuana leaves curling up and the edges turn brown. This is a very dangerous phenomenon that occurs to plants demonstrating distress and it could happen in both indoor and outdoor cultivation settings.

In terms of marijuana development and growth, the photosynthesis process can efficiently occur at a moderate level of temperature. Ideally, it is approximately 28° Celsius and any temperature beyond 30° Celsius is a dangerous level for the marijuana plants to get exposed to. Most especially when this dangerous level of temperature is incorporated with a low level of relative humidity, this scenario is extremely hazardous. When this occurs, not only you will notice marijuana leaves curling up, but even the new leaves sprouting will turn out twisted and gnarly, and eventually turn crispy brown and burned.

How to Fix This?

To fix this issue, any type of cultivator must be able to maintain an environment favorable and ideal for marijuana plant growth and development. To do this, as a cultivator you need to begin by controlling the distance of the plants from the light within the optimal extent. Constantly do this until the plants will begin its maturity stage. When cultivating indoors, take advantage of air conditioning equipment or fans to maintain a favorable atmospheric condition and keep the plants within the optimal temperature.

In terms of outdoor cultivation, to fix or prevent marijuana leaves curling up, it is beyond the cultivators’ choice that there are periods when the heat turns up than expected. This is the risky part of the outdoor, nonetheless, it can be fixed through establishing a shade made from a simple screen that protects that marijuana plants from getting to heat and maintain its cool despite environment situations. Expect that the claw leaves can no longer be back to a normal state, hence, it is necessary to remove them and give spaces for new leaves to sprout.


The possibility of marijuana leaves curling up can be caused by its natural genetic characteristics. This aspect is sometimes overlooked but genetics is the primary source of deficiencies and modifications in the growth of plants. When breeding marijuana plants, it is a topmost priority that the parents used during the breeding are at optimal health conditions. In this way, you are assured that the offspring are in the best health as well.

However, if the parents’ plants are not in the best conditions and have a history of clawing, genetics will be passed on to the next generation and result in poor marijuana plant characteristics. With this, the poor characteristics of the plants will eventually demonstrate marijuana leaves curling up and other signs of an inadequately developed breed.

How to Fix This?

To prevent marijuana leaves curling up, keep the plants at optimal condition by providing vastly needed feeding and watering, and put into consideration its condition before thinking of using it as a breeding parent. Research about the optimal growing needs of the marijuana plants according to its classification, as some types of strains have high sensitivity to some growing procedures.

Cold Temperatures

Marijuana leaves curling up can likewise cause by low temperatures. Apart from that, there is also discoloration may occur eventually. It is known among marijuana cultivators that at some point in the development of marijuana plants, especially during the late-blooming stage, the cold temperature can provide traces of purple colors on the plants, however, too much exposure can lead to plants death. Any temperature lower than 10° Celsius is a dangerous level among marijuana plants. This will even cause more risks when combined with high relative humidity and attracts rotting of buds.

How to Fix This?

To prevent marijuana leaves from curling up, the cold temperature must address effective immediately. For indoor growing, it is easy to increase the temperature within the area by increasing the lights while outdoor growing can be quite complicated and needs hard work. If possible, move the marijuana plants during the night time or make early harvesting.

Learn how to fix other problems that your cannabis is facing with the help of the best marijuana grow book!

Final Words

Indeed, cultivating marijuana plants is enjoyable and simple, however, no matter how easy as it might appear, it still imposes the distinct attention and maintenance it deserves. Remember that your final output and harvest will solely depend on the health condition of your crops.

When there is a sign of marijuana leaves curling up, then keep an eye on it and observe what might be the cause of the problem referencing from the above information. Once you recognize, render the best immediate cure it requires to save your precious marijuana plants from ultimately damaging and dying.