Cannabis Leaves Canoeing Upwards: 5 Common Reasons and Fixes

Cannabis Leaves Canoeing Upwards

Cannabis cultivation can be both a rewarding and challenging experience. One issue that cultivators, especially new growers, might encounter is the concerning presentation of “canoeing” cannabis leaves, where the leaf tips twist or curl upwards, resembling a canoe. This uncommon leaf pattern could signify a number of issues, including heat stress, nutrient burn, overwatering, excessive light intensity, or poor ventilation. This guide explores these problems in depth, their potential causes, and their effective fixes.

What is Cannabis Leaves Canoeing Upwards?

Cannabis leaves canoeing upwards refers to a peculiar leaf growth pattern often observed in stressed cannabis plants. The leaves’ tips and edges curl or twist upwards, giving the leaf a shape resembling a canoe. This phenomenon usually indicates that your cannabis plants are facing a stressor that affects their overall health and vitality. Common causes for canoeing leaves include heat stress, nutrient burn, overwatering, excessive light intensity, and poor ventilation.

It is essential to identify and address the underlying issue causing the upward curling of leaves, as this stress can lead to poor growth, decreased yields, and lower-quality flowers. By closely monitoring the grow environment and ensuring optimal conditions, cannabis cultivators can maintain healthy plants and avoid canoeing leaves.

Here are the 5 Common Reasons and Fixes

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1. Heat Stress

Exposure to excessively high temperatures can lead to heat stress in your cannabis plants – one major symptom being the ‘canoeing’ of leaves.


In an environment with high temperature, the plants try to reduce their leaf surface area exposed to the heat and light intensity, hence causing the leaves to curl up.

This issue can be exacerbated if your cannabis is housed in a small, enclosed growing space with poor ventilation, inadequate cooling mechanisms, or uncontrolled lighting systems.


  • Improve Ventilation: Ensuring proper air circulation is an effective way to reduce heat in your grow space. This could mean installing fans or upgrading your existing ventilation system.
  • Air Conditioning: For indoor setups where adjusting room temperature is possible, air conditioners or coolers could be a good investment.
  • Light Management: Consider adjusting the height and positioning of your grow lights. Lights placed too close to the plants can emit too much heat. Equally, excessively bright lights might need dimming.

2. Nutrient Burn

Nutrient burn or ‘nute burn’ refers to the damage caused to cannabis plants by excessive nutrients.


Over-fertilization leads to a buildup of salts in the soil which in turn leads to nutrient burn. The problem often presents itself as yellow or brown discoloration and ‘burnt’ patches on the leaves, often starting from the tips and margins, and can also cause the leaves to curl or ‘canoe’.


  • Flush Your Plants: Nutrient burn can be corrected by a thorough flush of the grow medium with pH balanced water. This aids in clearing away the nutrient buildup.
  • Less is More: Capitalize on nutrient sparsity. Cannabis plants typically require far less nutrients than new growers think.

3. Overwatering

Ironically, you can ‘drown’ your cannabis plants by watering them too much!


Overwatering disrupts the oxygen supply to the roots, causing various physiological changes including upward curling or ‘canoeing’ of the leaves.


  • Watering Schedule: Stick to a watering schedule that gives your plant just what it needs. Overwatered plants can be difficult to rehabilitate, but typically, allowing the plant to dry out before watering should help.
  • Look for Signs: Look for signs such as drooping or discoloration. A light pot typically means dry soil, indicating the need for watering.

4. Light Intensity

Like heat stress, plants can also suffer from ‘light burn’ due to overly intense light exposure.


Cannabis plants can tolerate a considerable range of lighting conditions, however, they do have their limits. Excessive exposure to strong light can cause light burn, which may manifest as yellow leaves that may canoe.


  • Adjust Light Distance: Keeping an appropriate distance between your plants and the light source could shield them from excessive light exposure.
  • Use Dimmable Lights: Dimmable lights can be useful for freshly transplanted or young plants who might not be ready to soak up high intensity light just yet.

5. Poor Ventilation

The importance of good ventilation in your cannabis grow space can never be overstated.


Insufficient airflow can lead to an array of issues for cannabis plants including dust build-up and pest problems, which could potentially cause the leaves to curl upwards or canoe.


  • Install Fans: Fans are an inexpensive, yet effective, way to boost air circulation within your grow space, ensuring the plant’s ability to respire properly.
  • Avoid Direct Breeze: It’s important to note, fans should not be pointing directly at the plants as this strong direct breeze could cause windburn.

Frequently Asked Questions: Cannabis Leaves Canoeing Upwards

Q1: Why are my cannabis leaves canoeing upwards?

Canoeing of cannabis leaves is typically a response to environmental stress. Factors such as heat stress, nutrient burn, overwatering, excessive light intensity, and poor ventilation can cause leaves to curl or canoe upwards.

Q2: Does heat stress cause cannabis leaves to canoe?

Yes, extreme heat can lead to cannabis leaves canoeing or curling upwards as the plant tries to minimize its exposure to heat. This curling can also be a sign of light stress from a light source that is too close or too strong for the plant to handle.

Q3: Could over-fertilization lead to leaf canoeing?

Absolutely! Over-fertilization often leads to a condition known as nutrient burn or “nute burn” which can manifest as curling or canoeing of cannabis leaves, often accompanied by yellowing or browning at the tips.

Q4: How do I fix cannabis leaves canoeing due to heat stress?

Improving ventilation, using air conditioning or climate control systems, and managing your lights efficiently to reduce excessive heat can help remedy heat stress.

Q5: Is overwatering a possible cause for leaf canoeing?

Yes, overwatering can cause leaves to canoe upwards. Overwatering can disrupt the oxygen supply to the roots, causing the leaves to curl or “canoe”. It’s usually best to allow the plant to dry out before watering again.

Q6: Can poor ventilation cause my cannabis leaves to canoe upwards?

Definitely! Insufficient airflow can lead to multiple issues including dust build-up, potential pest problems and, yes, the canoeing of leaves. Fans can help boost air circulation, but avoid directly blowing onto the plants to prevent windburn.

Q7: What should I do to fix cannabis leaf canoeing caused by excessive light?

Regulating the distance between your plants and the light source, as well as using dimmable lights, can help correct problems caused by excessive light intensity.

Q8: How can I prevent cannabis leaves from canoeing in the future?

The vital preventive measure is to maintain an optimal growth environment for your cannabis plants which includes adequate lighting, controlled temperature, appropriate watering, proper nutrients, and good air circulation. It’s about monitoring your plants closely and adjusting conditions as needed.

In Conclusion

‘Canoeing’ of cannabis leaves is a sign of stress. Though it might seem challenging to face, armed with these troubleshooting tips you’re now in a much better place to identify the possible causes and make the necessary adjustments. As every grow period progresses, you’ll find this experience vital in honing your skills to become a successful cannabis cultivator.

Remember, growing cannabis is a process of constant learning, adaptation, and experimentation. With each growth cycle, you are sure to become more skilled, observing the signs your plant provides, and being able to respond effectively to ensure a prosperous harvest.

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