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When Marijuana Leaves Turn Yellow


Cannabis plants can communicate the stress and nutrient deficiencies they experience. It is the responsibility of the grower to monitor the plant for any issues. One of the most common signs of plant stress is the yellowing of leaves. Chlorosis occurs when marijuana leaves turn yellow. It also occurs due to a lack of chlorophyll the green pigment essential during photosynthesis.

Chlorosis results from several factors and is often a sign of trouble. When marijuana leaves turn yellow, they lose their pigmentation. This means the plants can’t effectively synthesize light into the sugars essential for growth. Growers who identify chlorosis in their plants don’t need to panic. This article provides the causes of these issues so that you can easily remedy the situation.

Shortage of Nutrients

Usually, the discoloration or yellowing of the leaves is because of macro-nutrient deficiency. The yellowing of leaves on the lower fan leaves is also because of nitrogen deficiency. However, supplying sufficient nitrogen may still lead to yellowing. When marijuana leaves turn yellow it’s good to check the pH value. Usually, the deficiency results from the pH value of the medium or nutrient solution. When the soil or hydroponic solution’s pH value moves out of the desired range it causes discolouration. Correct pH values include 6-7 for soil, 5.5-6.5 for hydroponics. Specific nutrients will become unavailable for absorption, despite the amount of nutrients present.

Over- or Underwatering

Over- or underwatering cannabis plants can also make leaves turn yellow. Overwatering reduces the amount of oxygen around the roots, thus creating space for pathogenic anaerobic microorganisms. If the yellowing of cannabis leaves results from overwatering, it will become droopy. The yellowing leaves will also have copper or brown spots.

When marijuana leaves turn yellow, it can also be because of underwatering. Underwatering is a minor cause of yellowing. This is because less water isn’t sufficient to stress the plant to turn yellow. However, a clear sign of underwatering includes wilted foliage.

Temperature fluctuations

Temperature high influences cannabis leaves to turn yellow. If the ambient temperature fluctuates in not within a specific range (60-80°F), yellowing may occur. For lights off periods (night cycle), the temperature should be 60°F and above. During the lights-on period (day cycle), the temperature should be 80°F and below. A temperature that moves above the specific range for several days can lead to yellowing leaves.

The flowering stage also causes cannabis plants to lose some of their pigmentations. When yellowing occurs during the last phase of flowering, growers don’t need to worry. However, with yellowing that occurs during the vegetative stage, growers need to worry. Yellowing at the first phase of flowering requires action by the farmers.

Related Article: How many leaves does cannabis have!

Bottom line

When cannabis leaves turn yellow, it can be due to many reasons. It’s the grower’s responsibility to diagnose the exact causes of yellowing. Buying seeds from reputable sources can lead to great plants without deficiencies. This will also avoid any yellowing that results from the plant’s genetics. Also, ensure to water your plants without underwatering or overwatering them. Ensure to check the pH of the soil before planting your seeds. With all these helpful measures you can avoid yellow leaves.