Caring for cannabis plants can be a rewarding experience. However, even with the best care, your plants may sometimes exhibit signs of sluggishness or yellowing. Understanding the causes and taking prompt action can help prevent yellowing or revive your plants when it happens.
Key Takeaways
The Science Behind Yellowing Cannabis Leaves
When cannabis leaves turn yellow, the process of photosynthesis is impaired. This hampers their growth and development. The main culprit behind this color change is the degradation of chlorophyll, the green pigment responsible for absorbing sunlight and producing energy for the plant. The dominance of yellow or orange chloroplasts further contributes to the discoloration.
Watering Woes
Yellowing leaves are often caused by watering problems. Both excessive and insufficient watering can lead to this issue.
Excessive Watering
Providing too much water prevents oxygen from reaching the roots. Signs of overwatering include swollen, full-looking marijuana leaves. Poor drainage, such as the absence of drain holes in the pot or an oversized pot for a small cannabis plant, can exacerbate this problem. Adjusting your watering system, reducing the amount of water, or improving drainage can help prevent complete yellowing and revive your plants.
Underwatering
Underwatering manifests as thin and limp leaves. When multiple cannabis plants share a pot, each may not receive enough water. Forgetting to water on time can also contribute to this issue. Adjusting the amount of water for each watering session will ensure your plants receive adequate hydration.
Nutrient Deficiencies
Lack of nutrients, especially nitrogen, can cause leaves to turn pale or yellow. Nitrogen is vital for growth, particularly in new leaves. When nitrogen is insufficient, upper leaves may draw nitrogen from lower leaves, leading to yellowing and fading. Providing sufficient nutrients, including nitrogen, can prevent this issue. If correcting nitrogen intake doesn’t resolve the problem, other factors may be at play.
pH Imbalance
The acidity level of the water you use for cannabis can affect leaf health. The ideal pH is around 7.0. If the pH level is too low, the plant won’t be able to absorb sufficient nutrients from the soil. Maintaining the appropriate water acidity ensures healthy leaves.
Lighting Challenges
Proper lighting is essential for the growth and development of any plant, including cannabis. Lighting issues can contribute to yellowing leaves.
Burn Leaves
Excessive exposure to light or keeping the plant too close to a light source can cause the upper leaves to turn yellow. Moving the lamp away from the plant and adjusting the lighting schedule can resolve this problem.
Lack of Lighting
Insufficient light can cause lower leaves to turn yellow and become weak. Adjusting the light supply will help enhance leaf health.
Temperature Troubles
Extreme temperatures, either too high or too low, can stress cannabis plants and lead to yellowing.
Heat Stress
Temperatures above 28°C (80°F) slow down photosynthesis, resulting in yellowing leaves. Ensure adequate air circulation and provide temporary shade if growing outdoors to prevent overheating from lamps.
Cold Shock
Low temperatures can cause plants to wither and turn yellow, sometimes even developing a purple hue. Avoid overcooling, especially when growing in basements or outdoors.
Pests
Yellowing, weak leaves with spots and traces of insect bites indicate pest infestation. Preventive measures, such as limiting access to pets, proper watering practices, and cleanliness, can help deter pests. Fungal flies are a common pest that feeds on cannabis roots in humid environments. Appropriate watering and insecticides can aid in removing pests.
Identifying the Cause of Yellowing
Determining which leaves have turned yellow provides clues about the cause. Lower leaves often indicate nutrient deficiencies or lighting issues, while upper leaves suggest burn. However, preventing yellowing is easier than fixing it. Maintain proper watering, lighting, and nutrient supply to keep your plants healthy.
Cases When Yellow Leaves Are Natural
In some situations, yellowing leaves are natural and don’t require intervention. For instance, plants in the final stage of flowering often experience leaf yellowing. Adjusting the lighting and removing yellow leaves can maintain the overall health of the plant.
How to Revive Yellow Leaves on Plants
While seeing yellow leaves can be disheartening, there’s hope for recovery if you act promptly. Follow these steps:
- Identify the problem. Determine if yellowing is due to the natural aging process or chlorosis, the loss of chlorophyll required for photosynthesis.
- Identify the cause. Evaluate your watering practices, nutrient levels, pH, lighting, temperature, and potential pest issues.
- Work on a solution. Adjust your watering schedule, cleanse the soil, consider organic seaweed fertilizer, repot with balanced soil or regulate pH, control temperature, and adjust light exposure. Apply neem oil if pests are present.
- Trim yellow leaves. For mature plants, removing yellow and withered leaves can redirect energy toward healthy growth.
By diligently following these steps, you can bid farewell to yellowing leaves and enjoy the thriving greenery of your cannabis plants.
FAQ
Should We Cut Off Yellowing Marijuana Leaves?
It is acceptable to remove yellow and wrinkled leaves from mature plants. By doing so, you optimize energy distribution to healthier leaves and improve overall plant vitality.
Can Yellow Leaves Turn Green Again?
Once a leaf turns yellow, it is unlikely to restore its original green color, especially if it has become crispy. However, new leaves can sprout and restore the plant’s green appearance.
Why Do Marijuana Leaves Turn Yellow During Flowering?
Yellowing before the blooming period indicates the natural senescence process, which commonly occurs at the end of the growing season.
Remember, with proper care and treatment, yellowing of leaves can often be reversed. Don’t panic and remember that the patience and effort you invest in growing plants always pays off in the end.
