jeremymuszynski
New Member
Marijuana Plant Problems and Solutions Guide
Cannabis plants are resilient, but issues can arise during the growing process. Identifying and addressing problems early is key to healthy growth and good yields.
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1. Nutrient Deficiencies
Nitrogen Deficiency
Symptoms: Yellowing lower leaves, slow growth.
Cause: Insufficient nitrogen during the vegetative stage.
Solution: Feed with a nitrogen-rich fertilizer (e.g., fish emulsion, NPK 3-1-2).
Phosphorus Deficiency
Symptoms: Purple/red stems, dark green leaves with brown spots.
Cause: Low phosphorus, often in cold or acidic conditions.
Solution: Use a phosphorus-heavy nutrient mix (e.g., bone meal, NPK 1-2-3).
Potassium Deficiency
Symptoms: Edges of leaves turn yellow or brown, weak stems.
Cause: Poor potassium availability in soil or pH imbalance.
Solution: Add potassium sulfate or a bloom booster nutrient.
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2. Overwatering/Underwatering
Symptoms:
Overwatering: Drooping, yellow leaves, root rot.
Underwatering: Wilting, dry and crispy leaves.
Cause: Improper watering schedule or poor drainage.
Solution:
Overwatering: Let the soil dry out before the next watering. Ensure proper drainage.
Underwatering: Water consistently when the top inch of soil is dry.
---
3. pH Imbalance
Symptoms: Nutrient lockout, yellowing, brown spots, stunted growth.
Cause: Incorrect soil or water pH (soil: 6.0-7.0, hydro: 5.5-6.5).
Solution:
Test and adjust pH using pH up/down solutions.
Use pH-balanced nutrients.
---
4. Pests
Spider Mites
Symptoms: Small yellow/white spots, fine webbing under leaves.
Solution:
Spray with neem oil or insecticidal soap.
Introduce beneficial insects like ladybugs.
Fungus Gnats
Symptoms: Tiny flying insects, larvae in soil, drooping plants.
Solution:
Let the soil dry between waterings.
Add sticky traps and sprinkle diatomaceous earth on the soil.
Aphids
Symptoms: Sticky residue, yellowing leaves, clusters of small bugs.
Solution:
Spray with a mixture of water and dish soap.
Use neem oil or release lacewing larvae.
---
5. Mold and Mildew
Powdery Mildew
Symptoms: White, powdery substance on leaves.
Cause: High humidity, poor airflow.
Solution:
Increase airflow and reduce humidity.
Apply a sulfur-based fungicide or milk-water solution (1:9 ratio).
Bud Rot (Botrytis)
Symptoms: Gray or brown mold inside buds.
Cause: Excessive humidity during flowering.
Solution:
Remove infected buds immediately.
Keep humidity below 50% and increase airflow.
---
6. Light Stress
Light Burn
Symptoms: Yellowing tops, bleaching, crispy leaves.
Cause: Lights too close to plants.
Solution: Raise lights or reduce intensity.
Light Deprivation
Symptoms: Slow growth, small buds.
Cause: Insufficient light.
Solution: Provide adequate light for the stage (18+ hours vegetative, 12 hours flowering).
---
7. Heat or Cold Stress
Symptoms:
Heat: Leaf edges curl upward, yellowing, burnt tips.
Cold: Stunted growth, purple stems, drooping.
Cause: Extreme temperatures.
Solution:
Heat: Increase ventilation, reduce light intensity, maintain 70-85°F.
Cold: Use a heater or insulate the grow area, maintain 65-80°F.
---
8. Hermaphroditism
Symptoms: Male pollen sacs or “bananas” appear on female plants.
Cause: Stress (light leaks, heat, over-pruning).
Solution:
Remove hermaphrodite plants immediately to prevent pollination.
Maintain stable environmental conditions.
---
9. Slow or Stunted Growth
Symptoms: Plants not growing as expected.
Cause: Overwatering, nutrient deficiency, poor light, root issues.
Solution:
Address root health, improve light exposure, and check nutrients.
---
10. Harvest Timing Issues
Problem: Harvesting too early or too late.
Solution:
Use a magnifying glass to monitor trichomes:
Clear = too early.
Cloudy = ready.
Amber = relaxing effects.
Cannabis plants are resilient, but issues can arise during the growing process. Identifying and addressing problems early is key to healthy growth and good yields.
---
1. Nutrient Deficiencies
Nitrogen Deficiency
Symptoms: Yellowing lower leaves, slow growth.
Cause: Insufficient nitrogen during the vegetative stage.
Solution: Feed with a nitrogen-rich fertilizer (e.g., fish emulsion, NPK 3-1-2).
Phosphorus Deficiency
Symptoms: Purple/red stems, dark green leaves with brown spots.
Cause: Low phosphorus, often in cold or acidic conditions.
Solution: Use a phosphorus-heavy nutrient mix (e.g., bone meal, NPK 1-2-3).
Potassium Deficiency
Symptoms: Edges of leaves turn yellow or brown, weak stems.
Cause: Poor potassium availability in soil or pH imbalance.
Solution: Add potassium sulfate or a bloom booster nutrient.
---
2. Overwatering/Underwatering
Symptoms:
Overwatering: Drooping, yellow leaves, root rot.
Underwatering: Wilting, dry and crispy leaves.
Cause: Improper watering schedule or poor drainage.
Solution:
Overwatering: Let the soil dry out before the next watering. Ensure proper drainage.
Underwatering: Water consistently when the top inch of soil is dry.
---
3. pH Imbalance
Symptoms: Nutrient lockout, yellowing, brown spots, stunted growth.
Cause: Incorrect soil or water pH (soil: 6.0-7.0, hydro: 5.5-6.5).
Solution:
Test and adjust pH using pH up/down solutions.
Use pH-balanced nutrients.
---
4. Pests
Spider Mites
Symptoms: Small yellow/white spots, fine webbing under leaves.
Solution:
Spray with neem oil or insecticidal soap.
Introduce beneficial insects like ladybugs.
Fungus Gnats
Symptoms: Tiny flying insects, larvae in soil, drooping plants.
Solution:
Let the soil dry between waterings.
Add sticky traps and sprinkle diatomaceous earth on the soil.
Aphids
Symptoms: Sticky residue, yellowing leaves, clusters of small bugs.
Solution:
Spray with a mixture of water and dish soap.
Use neem oil or release lacewing larvae.
---
5. Mold and Mildew
Powdery Mildew
Symptoms: White, powdery substance on leaves.
Cause: High humidity, poor airflow.
Solution:
Increase airflow and reduce humidity.
Apply a sulfur-based fungicide or milk-water solution (1:9 ratio).
Bud Rot (Botrytis)
Symptoms: Gray or brown mold inside buds.
Cause: Excessive humidity during flowering.
Solution:
Remove infected buds immediately.
Keep humidity below 50% and increase airflow.
---
6. Light Stress
Light Burn
Symptoms: Yellowing tops, bleaching, crispy leaves.
Cause: Lights too close to plants.
Solution: Raise lights or reduce intensity.
Light Deprivation
Symptoms: Slow growth, small buds.
Cause: Insufficient light.
Solution: Provide adequate light for the stage (18+ hours vegetative, 12 hours flowering).
---
7. Heat or Cold Stress
Symptoms:
Heat: Leaf edges curl upward, yellowing, burnt tips.
Cold: Stunted growth, purple stems, drooping.
Cause: Extreme temperatures.
Solution:
Heat: Increase ventilation, reduce light intensity, maintain 70-85°F.
Cold: Use a heater or insulate the grow area, maintain 65-80°F.
---
8. Hermaphroditism
Symptoms: Male pollen sacs or “bananas” appear on female plants.
Cause: Stress (light leaks, heat, over-pruning).
Solution:
Remove hermaphrodite plants immediately to prevent pollination.
Maintain stable environmental conditions.
---
9. Slow or Stunted Growth
Symptoms: Plants not growing as expected.
Cause: Overwatering, nutrient deficiency, poor light, root issues.
Solution:
Address root health, improve light exposure, and check nutrients.
---
10. Harvest Timing Issues
Problem: Harvesting too early or too late.
Solution:
Use a magnifying glass to monitor trichomes:
Clear = too early.
Cloudy = ready.
Amber = relaxing effects.
