Cannabis Leaves Pointing Up: Causes, Prevention, And How To Fix Them

You walk into your grow room and your plant’s leaves are suddenly pointing up, as if they are praying. If you’re a beginner, you’re going to wonder why. Well, it’s not such a big deal that it can’t be fixed, but it’s not such a small issue that you can ignore it either. Your plants are experiencing a problem that’s common for many growers. 

Cannabis leaves can start curling and pointing up due to a plethora of reasons. If you don’t fix it, though, the problem may worsen and it may even take your plant’s life. In this article, we dive into why your cannabis leaves are pointing up and how to fix the issue. 

Causes for Cannabis Leaves Pointing Up

As mentioned earlier, there are various reasons why your cannabis leaves could start pointing upwards. In this section, we will go over the causes and the symptoms you’ll see when it happens.

1. Light Burn

Giving your cannabis plant a lot of light is good — it makes for good growth — but too much is not always a good thing, especially when it comes to cannabis plants. So, if you end up giving your cannabis plant a lot of light, expect it to experience light burn if you’re not careful enough. 

So, what is a light burn? It is the plant’s reaction to getting too much light. In other words, it’s the stress your plant experiences when it gets too much light. Usually, this problem occurs in indoor grow rooms where growers end up giving too much light to the plant for ultimate growth and yield. 

This is why it is important to use grow lights that replicate the sun’s quality instead of putting out as much light as possible. Usually, it is recommended that you give your plant 18 hours of light when it’s vegging and 12 hours of it when it’s blooming.

So, if your cannabis plant’s leaves are pointing up, the first culprit could be light burn. However, don’t get confused between healthy leaves and distorted ones. if your plant looks healthy in general but the leaves are perky, you’re in for a treat — you’ve found the sweet spot of lighting for your cannabis plant. 

You need to look for other symptoms. Here are the primary symptoms you’ll see on your cannabis plant if it is suffering from a light burn.

• Leaves Pointing Up 

The first symptom of a light burn is the leaves pointing up. Remember, leaves are the power generators of your plant where all the photosynthesis happens. So, if your cannabis experiences light stress, the leaves will start praying — sometimes, it may even seem like the leaves are trying to close in on themselves. 

Why does this happen? It’s the leaves trying to minimize the leaf surface so the amount of light it receives is reduced to more manageable, less stressful levels. 

• Bleached Leaf Tips

Another classic symptom of light burn is if the leaves are burnt on the edges or the tips. But this is also the symptom that your plant will show if it experiences nutrient deficiency, so you need to be a bit careful when diagnosing here. 

A simple way to distinguish the two is that with nutrient deficiencies, the leaves will also discolor entirely. On the other hand, light burnt leaves will only have bleached edges or tips. In severe cases of a light burn, the bleaching can spread inward, too. 

Additionally, this symptom will occur on the upper canopy of the plant since those areas are closer to the light and receive more light. 

The leaves start bleaching here because they stop chlorophyll production, which makes them lose their colors on the edges and tips. Like the leaves, even your precious buds may start looking bleached due to too much light. 

• Stunted Growth 

Another symptom of a light burn is your cannabis plant growing slower than expected or losing its vigor. Despite your expectations, more light doesn’t always guarantee more growth as anything in extremes is bad. 

• Dying Top Growth 

As mentioned earlier, the symptoms show up on the upper part of the canopy. Over time, these symptoms can worsen and the top part of your plant will start dying. Upper leaves will start yellowing, drying out, and dying off. 

Another point to note here is that with a nutrient burn, the yellowing leaves will still have green veins; in nutrient deficiency, the veins also lose color. 

2. Temperature Extremes

Extreme temperatures, whether too high or too low can affect your cannabis plants. Cannabis plants grow fairly easily, but they are sensitive to temperature changes and drastic deviations from their temperature range can trigger reactions that are noticeable on the leaves. 

If you’ve ever grown cannabis, you already know the importance of temperature. This is why growers in hot and cold climates get air conditioners and heaters to control the temperature. When it gets too hot, the leaves may tilt upwards to reduce the surface area exposed to strong sunlight, thus minimizing water loss through transpiration. Due to water loss, the leaves can also curl up or wilt as they seek to retain lost moisture. 

Not only can excessive heat disrupt processes in cannabis plants causing heat stress, but it will eventually affect the yields as well. As the plant gets stunted, it won’t be able to conduct the processes necessary to grow and reproduce, so temperature is an important factor when you grow marijuana. 

On the other hand, extremely cold temps can be equally detrimental to the plants. Known as cold stress, it can hinder metabolic reactions and slow down physiological processes that are important for plant growth and development.

Similar to heat stress, cannabis plants subjected to prolonged cold temperatures may start showing signs of curled-up leaves due to reduced metabolic activity. In short, the leaves curl as a defense mechanism when the plant tries to reduce exposure to cold temps or air and prevent any potential frost damage. 

Also, remember that the temperature is closely connected to the humidity.  High humidity encourages mold growth and pests while low humidity can dry out leaves causing them to curl or become crisp at the edges. If there's high heat with low humidity, the plants get stressed out and start curling their leaves. Conversely, cold temperatures paired with high humidity will set the stage for fungal diseases that contribute to leaf curling and other issues.

3. Nutrient Deficiencies 

Cannabis, like any other plant, needs nutrients to survive, so a deficiency or a combination of them can cause problems including leaf curling. You will see visible changes occur on the leaves as the plants try their best to conduct photosynthesis and maximize nutrient absorption. 

Cannabis plants are affected by several nutrient deficiencies, but here are a few common ones that can make the leaves curl up or down. 

• Nitrogen Deficiency

Nitrogen is essential for producing chlorophyll, which is crucial for photosynthesis. Without it, the leaves turn light green or yellow. As the deficiency worsens, the lower or mature leaves get affected first as nitrogen is a mobile nutrient. The leaves may start to curl or cup upwards as the plant tries to capture light for photosynthesis.

• Potassium Deficiency

Potassium is a critical element that’s involved in many functions from regulating water uptake to transpiration. Cannabis plants lacking potassium may show yellowing or browning along the edges of their leaves — a condition known as necrosis. In response to potassium deficiency, the leaves might curl up at the edges and take on a "taco" shape where the edges curl while the center remains flat.

• Magnesium Deficiency

Magnesium is extremely important for the plant to conduct photosynthesis as it serves as the main component of chlorophyll. As you can guess, the plants won’t survive without it. Plants deficient in magnesium often exhibit chlorosis. You may notice that although the leaf veins themselves are green, the area between them starts turning yellow. If you don’t supply magnesium to the plant at this point, the condition can worsen and the leaves start curling upwards at the edges. 

• Calcium Deficiency

Calcium plays a role in the development of cell walls and in maintaining the integrity of plant tissues. Lack of calcium can result in hindered growth and the leaves can start displaying irregular shapes and look distorted. In addition, they can become very vulnerable to other diseases. 

4. Watering Issues

One common reason for cannabis leaves pointing upwards is that you may not be watering properly. For instance, you may not have a schedule. Any deviations from the correct watering routine can make the leaves curl or point upwards. Or, you could be overwatering or underwatering the plants.  

• Overwatering

Cannabis plants need water but watering much more than necessary could be a problem. In this case, the plants are getting more water than they can use. Often, this leads to a reduction in oxygen that suffocates the roots. In severe cases, the roots can start rotting as well. When overwatered, cannabis leaves might start curling or cupping upwards as the roots struggle to function and take in nutrients efficiently.

• Underwatering

This occurs when plants don't get water to meet their hydration requirements. Low soil moisture levels hinder nutrient absorption and the leaves may wilt or droop. Cannabis plants may naturally tilt their leaves upwards to catch light and reduce water loss through transpiration. 

5. Pests and Diseases

Cannabis plants are susceptible to pests and diseases. Sometimes, you could be watering properly, and the plants may be getting all the nutrition they need, but you’ll still see the leaves curling. If everything is okay and the leaves still show some signs, it could be due to pests and diseases. Attacks from pests or infections can disrupt plant functions, resulting in changes in leaf shape and overall plant distress.

Pests

Some of the most common pests to attack cannabis plants are aphids, thrips, and whiteflies. The leaves can display various symptoms including tiny bite marks due to spider mites, but they will be so small that you may not notice it. 

Plants, under attack may display upward leaf curling or cupping as a reaction to pest-feeding activities. In addition, these pests cause a lot of stress to the plants. Generally, these sap-sucking insects release toxic substances or inject their saliva into tissues that prompt defensive reactions, resulting in leaf curling. At times, the leaves may also appear distorted. You’ll notice that they are stressed. 

Fungal and Bacterial Infections

Many types of fungal pathogens can attack your cannabis plants. Typically, it occurs due to bad watering practices and environmental conditions. If you don’t pay attention to the humidity, your plants can become very susceptible to fungal pathogens like powdery mildew and botrytis. 

These pathogens can quickly destroy the plants, Moreover, it’s not recommended to use buds infested with mold, so you must take care that your plants aren’t affected by them. Infected leaves may display curling or drooping due to tissue death, water loss, or nutrient deficiency caused by the presence of the pathogen. If the fungus has attacked the roots, the roots won’t be able to absorb the nutrients, so you may see symptoms that resemble nutrient deficiencies. 

Bacterial diseases like blight or leaf spot can also lead to leaf curling and changes in color as the plant works to limit the spread of infection.

How to Fix Praying or Pointing Leaves on Cannabis?

If your cannabis leaves are pointing up or curling, it’s not the end of the world — or at least your plant — yet. There are ways you can solve this issue, and more often than not, it involves adjusting your grow lights' position, especially if it’s due to a light burn.

Remember, the first thing you must do is remain calm. It may be daunting to deal with a plant that’s experiencing stress, but you don’t have to worry much. Usually, the problems mentioned above can be prevented and fixed as long as you act quickly.

1. Preventing and Fixing Light Burn 

Here are a few ways to fix or prevent light burn. 

• Raise Your Grow Lights 

You might be thinking you’ve kept your grow lights at the right distance, but sometimes, the light may be too close. This can happen due to several reasons, including miscalculations, human error, plants growing taller than expected, intense light throw, using wrong measurements, and much more. 

So, if the lights are too close to the plant, you simply have to move them further up. Don’t raise the height drastically, stick to a few inches for starters. If the problem persists, keep raising them until the symptoms ease up. 

It is recommended that you invest in a lux meter to detect the PPFD of your grow light. A lux meter measures the lumens falling at a specific surface, and PPFD refers to photosynthesis photon flux density, i.e., the amount of photosynthetically active light falling on a specific surface. 

A lux meter will give you the readings that you can convert to PPFD using a lux to PPFD online converter. 

• Train Your Plants 

In some cases, you may not be able to move the lights further up. For example, if you are growing in a grow tent or a closet, it gets difficult to do anything about the height. In such a case, you need to move your plant’s leaves away from the lights. Don’t worry, we’re not asking you to dig a hole in your home. 

Use training methods like LST, supercropping, bending, pruning, etc. to move the canopy away from the light. Since you already have plenty of light, training will not only fix the issue but may also give you a larger yield. 

• Prune Your Plant

On the other hand, you may have to make a sacrifice. If training isn’t an option, you can prune your cannabis plants. Here, you need to cut off pieces of the plant strategically. Usually, pruning is used to push the plant into survival mode and improve the yield, but here, your goal would be to bring the plant away from the light. 

• Maintain Other Growing Conditions 

When your plant gets a light burn, it may not always mean too much light. Sometimes, it could be a symptom of other problems. If the conditions of your grow room aren’t ideal, your plant may not be healthy enough. This can make it more prone to other problems, including light burns. 

Once the issues are fixed, you need to remember the final step: preventing it from happening again. 

If you’re regularly experiencing issues with light where your plants start curling or pointing up due to light burn, the first thing you can do is choose an appropriate strain for your grow room. There’s no point in growing a tall plant if you only have space for a fast version of the compact strain. Genetics play a big role, so pick strains that are known to grow shorter. 

How do you make sure the strain you get won’t negatively outgrow your expectations? Ensure you get your cannabis seeds from reputed seed banks that not only lab test their seeds but also provide detailed information about the strain, so you know exactly what you’re getting into. 

Next, you must be doubly sure when setting up the grow light, especially regarding the distance. Use the manufacturer’s recommendations, always — they know best. In any case, you should also use the hand test. 

Place your hand on the canopy and turn on the lights. If it feels warm on your hand, the lights are too close. Move them further up until they no longer feel warm on your hand. 

Here are some tips that will help you prevent light burns in the future:

• Make sure your growing environment is ideal for the plant to thrive in 
• Use the right type of grow lights for your plant 
• Maintain a grow diary or journal 
• Give your plant enough water throughout the day but not so much that you overwater it

2. Preventing Temperature Stress

When you’re growing cannabis indoors, the temperature will deviate slightly and that’s not a big deal. However, you should prevent drastic or sudden fluctuations and do your best to keep it within the recommended temperature range. Most strains will perform well with daytime temperatures ranging from 70°F to 85°F (21°C to 29°C) and nighttime temperatures between 60°F to 70°F (15°C to 21°C).

To keep the temps steady, you should also enhance air circulation and prevent heat from accumulating near the plants. This means that there should be no hot spots where heat collects in one place. So, get a couple of fans and make sure there’s plenty of air circulating and the plants get a good breeze as well. You can also use reflective materials like panda film and mylar to help the plants get more uniform light. 

And, of course, if the temperature is hard to control, you can always rely on heaters, coolers, and air conditioners to maintain the ideal range. 

If you notice that the leaves are curling, you need to take prompt action. If you fail to fix this issue, it will get worse with time. Therefore, track the temperature consistently using a hygrometer that displays both the humidity and temperature. 

As you can surmise, maintaining the temperature and humidity levels are crucial not just to prevent leaf curling, but you should do it to ensure the plants are healthy throughout their lifespan. 

3. Preventing and Addressing Nutrient Deficiencies

• Maintain proper pH Levels: It's important to ensure that the pH levels in the growing medium are within the appropriate range for nutrient absorption. Cannabis generally thrives in conditions with soil pH ranging from 6.0 to 7.0 and hydroponic systems from 5.5 to 6.5.
• Use High-Quality Nutrient Solutions: Opt for balanced fertilizers designed specifically to grow cannabis containing all the macro and micronutrients in ideal ratios. 
• Monitor and Adjust Feeding Schedules: Regularly check plants for signs of deficiencies so you can tailor the feeding routines according to the plant’s needs. Remember to feed the nutrients according to the plant’s stage of growth. 
• Proper Watering: Avoid both overwatering and underwatering as they can prevent the roots from absorbing nutrients properly and cause deficiencies. The soil should be moist — it should never be too wet or too dry. 

4. Preventing Watering Issues

Firstly, stick to a watering schedule tailored to your plant's needs and the type of soil you're using. Let the soil dry out a bit between waterings to avoid overwatering. Next, check the moisture levels in the soil regularly. Just stick a finger inside the soil and you’ll know. Water when the top soil looks dry. You can also lift your pot to check when to water. If the pot is too light, it’s time to water; if not, wait for a day or two. Once you grow a few plants, you’ll get the experience to water the plants at the right time. 

In addition, make sure that your pots drain well. Sometimes, even if you water properly, the containers can hold more water than required and cause waterlogging issues that eventually kill the plants. You can add perlite to the soil if needed to improve drainage and prevent waterlogging, which can lead to root rot. Also, add organic matter like compost if you have some on hand. 

Apart from watering at the right time, you should also pay attention to how you’re watering. Unless you’re using a foliar spray to provide extra nutrition or trying to get rid of pests, water only at the base of the plants rather than spraying the leaves to reduce the risk of diseases and help roots absorb water efficiently.

5. Prevention and Management of Pests and Diseases

When it comes to pests and fungal diseases, prevention is better than cure as it takes a while for the plants to recover from such problems. If you’re growing autoflowers, this is even more important as they don’t have the time to recover from such stressors and bounce back to produce good yields. 

Therefore, it’s best to start with a plan to prevent these problems in the first place. Now, you already know that humidity and improper watering can cause fungal problems. Start by monitoring humidity levels. Next, apply safe fungicides when the plants are still in their vegetative stage to prevent them in the future. If you detect problems early, your chances of avoiding major issues will increase. 

In addition, follow good sanitation practices by keeping your grow area clean and free of unwanted, dead plant material. Keep your tools clean as well. If any part of a plant is infected, prune it and toss it away so it doesn’t affect the entire grow room. 

It becomes difficult to contain pests and diseases, especially when they attack plants during the flowering stage. However, if it happens, spray the plants properly with fungicides. Don't spray the buds as they may change the taste. You can use neem oil mixed with insecticidal soap but it won’t eliminate the pests entirely. 

Summary: Cannabis Leaves Pointing Up: Causes, Prevention, And How To Fix Them

Cannabis is a funky plant to grow. Sometimes, a single growing season can be full of surprises. One such surprise is the plant’s leaves facing up or praying. The symptom may look scary, but it is often not. 

Praying leaves are usually caused due to light burns, and it is easy to fix the issue. You can either move the grow lights up or train your plant and manage their height. That’s it. Follow the steps listed above and keep the tips in mind to fix light burns on your cannabis plant.