Introduction
If you’ve ever noticed your cannabis leaves turning yellow? Then, it’s not just you! It is the age-old question many cannabis growers ask us. Well! Several factors contribute to this.
But worry not weed growers! We are here to help you to diagnose, treat, and prevent chlorosis in cannabis. And if you are with us till the end, we will help you with the tips that will keep your cannabis harvest bountiful in the harsh Canadian weather.
What do yellow cannabis leaves mean?
Seeing cannabis leaves turning yellow isn’t ideal, but it’s often a treatable sign of stress. Common culprits include nutrient deficiencies, like nitrogen, phosphorus, or potassium. The plant needs these for healthy growth; without them, leaves lose their vibrant green color.
Overwatering or underwatering can also cause yellowing. The plant needs consistent moisture, but soggy roots or dry soil can disrupt nutrient uptake.
Finally, environmental factors like extreme temperatures or incorrect light levels can stress the plant, leading to yellow leaves.
By identifying the cause, you can adjust your growing methods and bring your cannabis plant back to lush health.
Why are my Cannabis leaves turning yellow?
Yellow cannabis leaves are because of chlorosis common at the flowering stage. When you see cannabis leaves turning yellow, it’s often a sign of underlying issues like nutrient deficiencies, overwatering, or pests. Identifying and addressing the root cause promptly is crucial for maintaining plant health and vitality. It is the main concern among growers, and why not, after all, it is being planted with utmost care and patience. It is important to prevent and address the causes of foliage fading and loss of color early. Here are the factors to address:
1. Nutrient Deficiencies
Nutrient deficiency such as Calcium and Magnesium causes cannabis leaves to turn yellow. During the flowering stage, increase the intake of three essential macronutrients- Nitrogen, Phosphorus, and potassium (NPK). For that, get a well-balanced organic fertilizer specially formulated for cannabis, and do not overdo it.
Yellow leaves in cannabis can often signal a nitrogen deficiency, notably when yellow spots begin showing on the plant’s lower side. These affected leaves are usually smooth to the touch and easily torn, contrasting with dry, tough-to-tear yellow leaves that would suggest a different issue. Nitrogen deficiency often arises in plants that have exhausted the soil’s nitrogen supply, a common scenario when cannabis remains in the same pot for an extended period without adequate nutrition. Typically, this problem doesn’t occur if the plant has been receiving the suggested nutrient mix via its watering routine.
Fortunately, rectifying a nitrogen deficiency is straightforward:
- Administer a nitrogen-rich nutrient solution to the plants, ensuring they receive the necessary amount of this critical nutrient.
- Repot the cannabis into a new container filled with fresh, aerated soil to rejuvenate its environment.
Besides nitrogen, other deficiencies can also cause yellowing in cannabis leaves. It’s essential to understand these to maintain plant health effectively.
Related: Nitrogen: The Silent Hero For Healthy Cannabis Plants
2. pH Imbalance
Do you know how alkaline your water is? What happens is alkalinity damages the roots, and plants start leaf discoloration. It is the most common mistake growers do. For cannabis soil planted, the ideal pH is 6-7, while for hydroponics, the optimal pH is between 5.5-6.5.
Improper pH causes nutrient lockout, which is why leaf color changes. It also happens when you are overfeeding nutrients. So, get a pH tester to check for pH and TDS solids. If it’s a nutrient issue, flushing the soil before feeding the plant again may help.
3. Light Deficiency
Why do plants require proper sunlight? The answer is simple: to perform photosynthesis. It is possible only when leave produces enough chlorophyll. When you grow a plant indoors, you mimic the environment to grow plants with grow lights. If the grow lights are too close, it will cause perspiration turning leaves and flowers yellow. But if it’s too far or low, there will be the same issue. For optimum growth, refer to the manual provided with the grow lights. Increase or change the lights if the light is too low. CFL bulbs are best for indoor cannabis cultivation.
Also Read: Cannabis Seeds Growing Indoor Guide
4. Incorrect Watering
Watering your cannabis can be tricky! Both too much and too little can make the leaves pale. Fabric pots soak up extra water, so be careful.
Overwatering drowns the roots, like suffocating underwater. They can’t get nutrients, and leaves turn pale. Underwatering makes your plant thirsty and stressed. Leaves get thin, leggy, and even crispy.
A hygrometer is your friend! It tracks moisture in the soil, so you know when to water. Aim for consistently moist, not soggy, soil. Look out for curling or pale leaves, which can mean watering problems.
Fix it by adjusting your schedule: Less water for overwatering, more for underwatering. With practice and your hygrometer, you’ll be a watering pro, keeping your cannabis plants vibrant!
5. Pests
Those white fungus gnats on your leaves are leaf septoria destroying your little marijuana. You know your plant is being attacked when you see white or black spots on yellow leaves. They start in small yellow circles and turn brown.
They may enter from pets, outdoor environments, soil, etc. Diseases and pests are the worst of all, and you cannot ignore them. Get some ladybugs that will be a natural alternative to pesticides. You can check wikiHow to learn for pest control in tents or make your natural pesticide via neem oil.
6. Temperature Problem
Generally, overlighting causes overheating. The closer the light is, the more heat is generated and leaves yellow. The best way is to check yourself by placing your hand close to the plant, if you feel hot, it’s way too hot for your cannabis plants. You can even check via thermometer, either reduce lights, place them far away, or install fans and air conditioners for air circulation in your grow tents.
Similarly, if it’s too cold and the temperature is below 10 degrees, cannabis will turn yellow, bluish, or purple. For that, install heaters or increase the light in the growing area. You can also make a DIY greenhouse for outdoor pest control.
7. Over or Under Fertilization
While trying to give your cannabis plants a boost, it’s easy to overdo it with fertilizer, even organic options. Start slow and follow recommended feeding schedules, adjusting as you learn your plants’ needs.
Yellowing leaves can be a sign of feeding issues. If the yellowing starts at the tips and progresses inwards, it often indicates overfeeding. Excess nutrients can build up in the soil, burning the leaves. In contrast, leaves turning yellow from the bottom up might suggest underfeeding.
By recognizing these patterns, you can adjust your feeding regimen. If overfeeding is the culprit, flush the soil with plain water to remove excess nutrients, then wait for signs the plant needs feeding again before resuming with a lighter dose. This careful monitoring will help you find the sweet spot to keep your cannabis plants happy and thriving.
8. Root Rot
It is vital to know how widespread is the yellowing. Is it affecting just a few leaves or the entire plant? If you see those tiny little yellow spots all over the cannabis, it may be due to root rot. It is a microbial condition in roots caused by overwatering or waterlogging. This forms algae, fungi, and bacteria that attack the roots and start root decay to brown, slimy roots and yellow leaves.
If the roots are in a bad state, switch from ceramic to air pots for aeration for prevention. Mycorrhizal fungi will kill the bacteria if introduced to the soil. Reduce the water schedule and change the pot.
Also Refer to Choosing the Right Container for Growing Cannabis: Maximizing Quality and Yield
9. Leaf septoria
Leaf septoria, also known as yellow leaf spot, is a fungal affliction causing cannabis leaves to yellow. It manifests as small, circular yellow spots on lower leaves, which eventually turn brown, surrounded by a yellow outline. If ignored, this disease can ravage your entire plant, potentially leading to its complete removal.
To combat leaf septoria, start by meticulously removing all infected foliage to halt the fungus’s spread. Following that, applying a copper-based fungicide can effectively manage the infection.
Preventing leaf septoria involves ensuring a dry, well-ventilated grow space, as the fungus thrives in moist, humid conditions. Be cautious not to wet the leaves during watering and consistently clean and disinfect your gardening tools and hands to avoid contaminating your plants.
How to Determine the Cause of Yellowing?
Determining the exact cause of yellowing leaves in your cannabis plants requires some investigating. Here are the steps to help you:
1. Observe the yellowing pattern
If discoloration occurs on older leaves at the bottom, it is normal as the plant shifts resources to younger leaves. The yellowing between veins on older leaves hints at a magnesium deficiency.
Similarly, lower leaves yellowing first, then progressing upwards is a sign of nitrogen deficiency, underwatering, or root issues, and the last is yellowing starting on newer growth, including tips and edges indicating overwatering, nutrient burn, light burn, or pest damage.
2. Consider the stage of growth
Some yellowing during the flowering stage is normal. However, excessive yellowing throughout the plant could signal nutrient deficiencies or other issues. For that, check the soil moisture, and inspect the roots. If the root is white and firm, it’s healthy. If it’s brown and mushy roots maybe you are overwatering.
Also Read: Troubleshooting Guide
How to fix Yellow leaves on Plants?
To fix yellow coloration on cannabis leaves, first identify the cause, if there are any other concerning symptoms present (wilting, stunted growth). Now you know what is causing your cannabis to turn pale. It’s time to fix the leaf’s yellowing. Do it by:
1. Maintaining a Balanced Diet
Use a high-quality cannabis-specific nutrient solution throughout the growing cycle, adjusting the NPK (nitrogen, phosphorus, potassium) ratio based on the growth stage and testing your soil to identify potential nutrient deficiencies before they cause yellowing.
2. Water Wisely
Use a moisture meter or finger to check soil moisture. Water deeply when the top inch of soil feels dry, allowing proper drainage to prevent overwatering. Aim for consistent watering throughout the growth cycle, avoiding periods of drought or extreme wetness.
3. Optimize the Environment
When you see cannabis leaves turning yellow, it might be because they’re not getting enough sunlight or the soil pH is wrong. Maintain a slightly acidic pH level between 6.0 and 7.0 in your soil or growing medium for optimal nutrient uptake by the plant. Keep the temperature within the recommended range (ideally 68-78°F) and humidity levels appropriate for the growth stage to prevent stress-induced yellowing. Provide adequate light intensity but avoid light burn by maintaining a safe distance between the light source and the plants.
4. Preventive Maintenance
Regularly inspect your plants for signs of pests or diseases and take prompt action to control them before they damage the leaves. Ensure proper air circulation around your plants to prevent moisture buildup and promote healthy growth.
5. Choose Resistant Cannabis Strains
Consider cannabis strains known for their resilience to nutrient deficiencies and other stressors that can cause yellowing. Auto-flowering seeds and hybrid strains are the perfect solution to these problems. Using healthy seedlings from reputable sources reduces the risk of inherent weaknesses that could lead to yellowing later.
Remember, if you implement these preventative measures, you can create a healthy and stable environment for your cannabis plants, minimizing the chances of encountering yellow leaves and ensuring successful growth.
Also Read: Harvesting Cannabis Buds: Tips, Tricks, and Expert Advice
Vigilance Is Key to Prevention
When you notice your cannabis leaves turning yellow, it’s crucial to approach the situation calmly and analytically. This symptom can stem from various issues, including nutrient deficiencies, watering errors, and environmental stressors.
Panicking won’t help; instead, carefully assess the plant to identify the specific cause of the yellowing. This might involve checking for signs of over or under-watering, testing soil pH, or evaluating nutrient levels.
By maintaining a vigilant watch over your cannabis plants, you can catch early signs of distress and address them promptly. Regular monitoring allows you to adjust care practices before minor issues escalate into significant problems.
Effective prevention of yellowing cannabis leaves involves a proactive mindset, ensuring the plants’ environment and care regimen are consistently optimized for their health. Staying ahead of potential issues through diligent observation and maintenance can lead to a healthy, bountiful cannabis crop, minimizing the chances of encountering yellow leaves
Cases when Cannabis Leaves Turning Yellow is not a problem?
Ask yourself- How quickly are the leaves turning yellow? Is it a gradual process or happens rapidly? Yellow leaves are a natural process, so do not panic if you observe yellowing. Especially during the vegetative stage and flowering stage, leaves do turn yellow. It is because the plant relocates energy via photosynthesis to generate flowers.
If you notice older cannabis leaves turning yellow at the end, yet the plant seems healthy overall, there’s likely no cause for concern. Embrace the natural life cycle, as flushing during the flowering stage can enhance the taste of cannabis flowers.
Also Refer to: What Tools and Equipment Do You Need To Grow Cannabis?
FAQs on Issues of Yellowing Leaves in Cannabis Plants:
Let’s discuss frequently asked questions on why the cannabis leaves are turning yellow:
Q: How do you fix yellow leaves on plants?
The solution depends on the cause of the yellowing. Start with identifying the cause, addressing and then providing proper care. There are many reasons, such as watering habits, nutrient deficiencies, pests, diseases, or plants getting older.
Q: What deficiency causes the yellowing of leaves?
Three nutrients cause nutrient deficiency in plants- NPK. Where nitrogen deficiency turns lower leaves pale yellow, magnesium deficiency causes yellowing between veins of older leaves, sometimes with a reddish tinge. The iron deficiency causes young leaves to turn pale yellow, with veins remaining green.
Q: What do overwatered cannabis leaves look like?
Overwatered cannabis leaves lead to the entire yellowing of the plant often starting with lower leaves. The leaves may feel soft and limp. There are also signs of browning or mushiness at the base of the stem and roots.
Q: Can a yellow leaf turn green again?
Unfortunately, no. Once a leaf loses chlorophyll, it cannot regain its green color. However, you can prevent further yellowing and focus on the health of new growth.
Conclusion
When you see cannabis leaves turning yellow leaves next time, don’t panic because it is common among growers. Look for solutions, identify the cause, and take corrective action to get your plants back on track. Knowing where it starts, how it progresses, and if it affects new or old growth provides valuable clues. Check for the signs the plant gives you. To save the plant, you need to get through the root cause. Just be patient!
Still unsure about the cause of yellowing? Consult online resources or reach out to experienced cannabis growers for further guidance.
