Cannabis leaves turn yellow, why exactly?

Posted on Aug 08 , 2024

Are you anxious when you see the hemp leaves turn yellow? Don't panic first, find the cause to prescribe the right medicine, let's analyze it carefully.


First of all, where exactly is the yellowing part?


Cannabis leaves turn yellow

1. The lower leaves turn yellow

The lower blades turn yellow, and the problem may lie in the following areas:


  • Nutritional deficiencies: Is it a nitrogen deficiency? Without it, plant nutrition can't keep up, and leaf tips are the first to be unlucky.


  • Improper watering: Watering too much or too little, the water does not meet the needs of the plant or exceeds, which will lead to a decrease in the ability of the roots to absorb nutrients, and the leaves will also be affected.


  • Lack of light: The lower leaves are not exposed to the sun and may turn yellow.



So how do you fix this situation?


First of all, you can check the soil moisture first, insert your finger into the soil for 5 cm, feel if the soil is too dry or too wet, if there is nothing wrong with the soil. Then check that the leaves are not exposed to the sun, adjust the position of the grow light or prune the shaded leaves, so that the light is evenly distributed.

If that's all right, it's undernourished.


With a soil testing tool, the soil nitrogen content is detected, the seedling stage is 10-50 ppm, the growth stage is 50-200 ppm, and the flowering stage is 10-50 ppm, if the nitrogen content is low, add an appropriate amount of nitrogen fertilizer when watering.


2. The middle leaves turn yellow

The middle leaves turn yellow, and the problem may lie in the following areas:


Unbalanced pH: If the pH of the soil or hydroponic system is not right, the plant will not be able to absorb nutrients efficiently.


Lack of magnesium and iron: Magnesium and iron are essential trace elements for plants


Pests and diseases: Have the leaves been carefully inspected? Attacks by fungi, bacteria, or insect pests can be the culprits that cause yellowing of leaves, which can damage the plant's cellular structure, affect its normal physiological functions, and turn the leaves yellow.


So, how do you fix this?


Check the pH value first, use a pH testing tool to see how much the pH value of the soil is in at the moment, and if it is between 5.5-6.5, you don't need to adjust it. Next, check to see if there is a problem with pests and diseases, and check the surface of the leaves.


If there is nothing wrong with either of these, then it may be a magnesium or iron deficiency.

Nutrients are supplemented by foliar sprays or by adding these elements to the soil.


3. The upper leaves turn yellow

The yellowing of the upper leaves may be due to:

Nutrient overload: Too much nitrogen, which burns the leaves.

Too much light: The sun or grow lights are too strong, and the leaves can't stand it.


So, how do you fix this?


Reduce nitrogen fertilizer use, avoid nitrogen fertilizer excess, and maintain appropriate nitrogen levels; Adjust the light intensity, adjust the position and intensity of the grow light appropriately, and avoid excessive light.


The problem of yellowing of cannabis leaves is not something that can be solved in one or two sentences, it is more about more observation, more practice, to find the root of the problem, and to suit the remedy to the case, I hope this article can help you.

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