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If the leave on your marijuana plants are dying off for reasons you can’t explain, it is time to figure out what is behind it. There are generally three reasons for the dying off of your plants’ leaves: a pH imbalance, too much or too little water for your plants, or nutrient deficiencies and toxicities.
Read this article and learn how to recognize leave problems and how to fix leave problems.
Tip: make sure to download my free Grow Bible for more information
Start with the possibility of a pH imbalance and go from there to diagnose the problem and find a way to fix it before it’s too late.
Signs of dying leaves
If you start noticing that your leaves are discolored, they are probably starting to die off. This discoloration can come in the form of yellow, brown, grey, or even red. The leaves might be curling one way or the other (up or down), or just dropping off the plant after yellowing or browning, signifying their death.
How to fix sick leaves
In order to know how to stop the trend of leaf death that is plaguing your plants, you are going to first need to know which of the top three causes is at fault. Is the pH level in the roots imbalanced?
Have you been over or under watering your marijuana plants? Are there nutrient toxicities or deficiencies that are causing the problem? These are all questions you need to ask yourself when trying to know how to fix the problem.
A pH imbalance is the most common reason your plants will be struggling with keeping its leaves happy and healthy. This is simply because the correct level of pH is necessary before your plant can even take in nutrients. That, in turn, means that a fixed pH level could actually solve any nutrient deficiencies or toxicities that your plant is having. So, whenever you see that something is off with your plant, always check the pH level near the roots before doing anything else.
In case you haven’t delved into the topic of pH before, the pH scale measures the acidity and alkalinity of a solution, gauging it via a range of 0 through 14. If it’s lower than 7, the solution is acidic. If it’s higher than 7, the solution is alkaline. Therefore, the pH level of 7 is perfectly neutral – pure, uncompromised water has a neutral pH level.
You don’t need to be a scientist to check the pH level of the soil. The most important part to check is the soil right around the root system of your plant. While the pH level doesn’t need to be perfect, it will enable you to figure out if there is a pH balance problem. It is useful to allow the pH range to fluctuate a bit over time because this will actually allow certain nutrients be absorbed at different rates, which can be helpful to your plant.
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You will need to have a way of maintaining and managing the pH level throughout your plant’s life. One way to do this is by testing the water/nutrient (or supplement) solution before you feed it to your plants. Simple use something like pH Up/Down to adjust the pH level until it’s within the ideal range. You can do this by using natural means, as well. You can add vinegar to the solution to lower the pH level, for instance, or you can simply whisk the water (which adds oxygen) to bring the pH level up. Another way of raising the pH level is by adding dolomite lime to the soil. This has the added benefit of also adding calcium and magnesium to the soil medium.
The ideal pH level for roots to absorb all nutrients efficiently is between 6 and 7. Any higher or lower than that, and you could start running into problems. If you are using a hydroponic growing system, however, then you are going to want to range to instead be between 5.5 and 6.5.
If this adjustment before feeding your plants hasn’t solved the problem, there are other ways to check and adjust the pH level. If your plants are in pots of some sort, you should try collecting the water that is draining from the holes on the bottom. This runoff water should be tested for its pH to see what really goes on near your roots. If you feed your plants a nutrient-water solution that was at a pH of 6.0, for instance, and the runoff water measures up to a pH level of 4.0, you know there is a buildup of some nutrient that needs to be removed before your plant’s roots can function properly. This buildup affects the pH level of the soil around your plant’s roots and, therefore, keeps the roots from effectively absorbing all the nutrients they need to.
You can remove a buildup (such as a salt buildup) by flushing the system with three times the normal amount of plan, pH-balanced water. After that, you can feed them normally, but make sure to continue monitoring the pH levels to know if the flush was successful. Some growers perform a routine (every 3 weeks or every month) flush of their plants anyway to prevent buildups from occurring. This is probably not crucial, however unless you consistently give your plants too many nutrients.
If you’re growing in a hydroponic system, the pH tends to rise over time as the oxygen content in the water increases. Your best way of ensuring a stable pH level is checking consistently until you are familiar with how the pH level rises or lowers in your particular system.
If you have fixed the pH level and your plants are still experiencing dying leaves, you need to look elsewhere for the cause. One such cause could be the incorrect watering of your marijuana plants. You can diagnose what the exact issue is depending on your growing medium. If you are growing your plants in soil or in coco coir, for example, (or another similar soilless medium), the problem most likely lies with poor drainage, too much watering, or too little watering.
You can follow certain steps to ensure that your plant is receiving the right amount of water. Each time you are watering your plants, you should add the correct amount to make sure about 20% of it has drained out as runoff water. After you have done this, wait to water them again until the soil is dry enough. You can establish if the soil is dry by poking your finger in and making sure it’s dry until the top knuckle.
Of course, if you are growing your plants in a hydroponic setup, then over or underwatering will not be the issue since you don’t even water your plants. They could, however, be “drowning” due to a lack of oxygen. Use an air stone to get more dissolved oxygen into the water.
If your plants have root rot (whether in a hydroponic or soil-based growing system), the roots will be brown, mushy, and stinky. This can also come from improper watering, poor drainage, or high temperatures – then again, sometimes root rot seems to appear out of nowhere, for no logical reason.
If your plants do get root rot, get rid of it with Aquashield. Other root supplements that can be used are Great White and Subculture B.
If you have ensured that improper watering or an imbalanced pH level aren’t the issues, then your plants likely have a nutrient deficiency. You should read up on the symptoms of each nutrient deficiency (or toxicity) to establish which one your plant is struggling with.
Read the article Nutrient deficiencies in marijuana plants for a list with pictures of all possible nutrient deficiencies
List of marijuana plant symptoms
– Curling up of edges
– Curling down of edges
– Falling off
– Leaf death
When it comes to the pH level, it is valuable to know that the nitrogen content in a nutrient system has the strongest effect on the pH of the water. You, therefore, can use this to mix the right nutrients together according to the current water pH levels, so the nutrients are self-correcting the pH level without any extra hassle.
Thanks for reading. Please leave comments or questions below and don’t forget to download my free grow bible
The founder of I Love Growing Marijuana, Robert Bergman, is a marijuana growing expert that enjoys sharing his knowledge with the world. He combines years of experience, ranging from small-scale grows to massive operations, with a passion for growing. His articles include tutorials on growing... [read more]