How to Fix Yellow Leaves on Cannabis Plants: Diagnosis & Remedies

Yellow leaves on cannabis plants are one of the most common issues growers face—and one of the most misunderstood. Is it overwatering? Nutrient deficiency? Light burn?

Here’s how to properly diagnose yellowing leaves and bring your plants back to full health.

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Common Causes of Yellow Leaves

1. Nitrogen Deficiency

• Symptoms: Older leaves turn yellow and drop off.
• Fix: Use a balanced vegetative nutrient mix with adequate nitrogen.

2. Overwatering

• Symptoms: Drooping, yellowing leaves and soggy soil.
• Fix: Improve drainage and let soil dry out between waterings.

3. Underwatering

• Symptoms: Dry, yellow, crispy edges.
• Fix: Increase watering frequency, especially in hot/dry conditions.

4. pH Imbalance

• Symptoms: Yellowing alongside spotting or burnt tips.
• Fix: Test soil or water runoff. Ideal pH is 6.0–6.5 (soil) or 5.8–6.2 (hydro).

5. Light Burn

• Symptoms: Yellowing near the top leaves closest to grow lights.
• Fix: Raise your lights or reduce intensity.

6. Root Issues / Rot

• Symptoms: Yellowing leaves with stunted growth and foul smell in medium.
• Fix: Improve airflow, consider transplanting, and apply root-friendly microbes.

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Tools for Diagnosis

• Soil pH Tester
• Moisture Meter
• Magnifying Glass (to check for pests)
• TDS Meter (for measuring nutrient levels)

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Prevention Tips

• Always check pH and EC levels before feeding
• Let soil fully dry between waterings
• Don’t overfeed nutrients too early
• Keep grow space clean and well-ventilated
• Use healthy, pest-free clones or seeds

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When to Worry

• If yellowing is rapid and spreading to new growth
• If multiple deficiencies are present at once
• If combined with curling, browning, or leaf drop
  In these cases, consider flushing your plant with clean water and starting with a light nutrient mix after 24–48 hours.

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Wrap-Up: Don’t Panic, Diagnose First

Yellow cannabis leaves don’t always spell doom. In many cases, they’re simply your plant’s way of asking for help. Diagnose the problem carefully, correct it promptly, and your plants will bounce back stronger than ever.

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