Common Problems & Solutions Page
Common Cannabis Problems & Solutions
Identify and solve common issues affecting your cannabis plants. From nutrient deficiencies to pests and environmental stressors, this interactive guide helps you diagnose problems and find effective solutions quickly.
Plant Problem Diagnosis Tool
Where are you seeing the problem?
Leaves
Stems
Roots
Buds/Flowers
Whole Plant
What symptoms are you noticing?
Yellowing
Spots/Patches
Curling/Twisted
Wilting/Drooping
Burning/Crispy
Other Discoloration
Additional Details
Diagnosis Results
Analyzing symptoms...
Prevention Tip:
Regular monitoring is key to early detection. Check your plants daily for any signs of problems, focusing on new growth and the undersides of leaves.
Cannabis Problems Browser
Nitrogen Deficiency
ModerateYellowing of older leaves starting from the bottom of the plant and progressing upward. Slow growth and smaller leaves overall.
- Yellowing (chlorosis) of older, lower leaves first
- Progressive yellowing moving up the plant
- Slow, stunted growth with smaller leaves
- Stems may develop purple or red coloration
- In severe cases, leaves will drop prematurely
- Insufficient nitrogen in growing medium
- pH imbalance preventing nitrogen uptake (ideal pH: 6.0-6.5 soil, 5.5-6.0 hydro)
- Overwatering leading to nutrient lockout
- Natural nitrogen depletion during flowering stage
- Poor quality or depleted soil without amendments
- For soil: Add nitrogen-rich fertilizer or amendments like blood meal
- For hydro: Increase nitrogen ratio in nutrient solution
- Check and adjust pH to optimal range for nitrogen uptake
- Ensure proper watering schedule (allow soil to dry slightly between waterings)
- Note: During late flowering, some nitrogen deficiency is normal and may not need correction
Phosphorus Deficiency
ModerateDark purple or reddish stems and leaf veins. Slow growth and delayed flowering. Most common in cooler growing conditions.
- Dark purple or reddish coloration on stems and leaf veins
- Leaves may develop a dark blue-green color
- Growth becomes noticeably stunted
- Leaves may develop bronze or purple spots
- Delays in flowering and reduced yields
- Cold growing conditions (phosphorus becomes less available below 15°C/60°F)
- pH imbalance (phosphorus is most available at pH 6.2-7.0)
- Insufficient phosphorus in the growing medium
- Compacted soil or poor root development
- Excessive iron or zinc in the growing medium
- Increase growing temperature to above 20°C (68°F) if possible
- Adjust pH to optimal range (6.2-7.0 for soil, 5.5-6.2 for hydro)
- Add phosphorus-rich nutrients (look for higher P value)
- For organic grows, add bone meal or rock phosphate
- Ensure proper root zone aeration to improve uptake
Spider Mites
SevereTiny yellow/white speckling on leaves, fine webbing between leaves and branches. Can quickly devastate a garden if left untreated.
- Fine stippling/speckling of tiny yellow or white dots on leaves
- Web-like material between leaves and branches
- Leaves may appear dusty or speckled
- Tiny moving dots visible with magnification
- As infestation progresses, leaves yellow and die
- Hot, dry conditions (ideal breeding environment)
- Introduction from other infected plants
- Introduction from outdoor environments
- Poor quarantine procedures for new plants
- Low humidity (below 40%)
- Biological control: Predatory mites (Phytoseiulus persimilis)
- Neem oil application (every 3-5 days for 2-3 weeks)
- Insecticidal soap applied to all plant surfaces
- For severe cases, spinosad products or food-grade diatomaceous earth
- Increase humidity to above 60% and maintain good airflow
- For extreme cases: Consider starting over after thorough environment cleaning
Powdery Mildew
ModerateWhite powdery substance on leaves and sometimes buds. Spreads quickly in high humidity conditions with poor air circulation.
- White, powder-like fungal growth on leaves and stems
- Usually begins on upper leaves and moves downward
- Affected leaves may yellow and curl
- Can spread to buds in severe cases
- Reduced photosynthesis and plant vigor
- High humidity (above 60%) combined with poor air circulation
- Temperature fluctuations (especially cooler nights)
- Overcrowded plants with poor spacing
- Water on leaves during dark periods
- Spores introduced from outside environment
- Improve air circulation with fans
- Reduce humidity to 40-50% during flowering
- Remove severely affected leaves
- Apply treatment: Potassium bicarbonate solution (2g per liter of water)
- Milk spray (1:9 milk to water ratio) can be effective for early stages
- Silica supplements can help strengthen plant resistance
Heat Stress
ModerateLeaves curling upward at the edges (taco shape). Growth slows and flowers may develop loose, airy structure.
- Leaves curl upward along the edges forming a "taco" shape
- Yellow or brown leaf edges
- Leaves feel dry and brittle
- Stems may stretch and become thin
- Flowers develop loose, airy structure rather than dense buds
- Temperatures above 28°C (82°F) for extended periods
- Grow lights placed too close to canopy
- Inadequate ventilation or airflow
- Low humidity intensifying heat effects
- Hot, dry winds in outdoor grows
- Improve ventilation with additional fans
- Increase extraction rate to remove hot air
- Raise lights further from canopy
- Consider air conditioning for consistently hot environments
- Water more frequently (but don't overwater)
- Provide shade during peak heat periods for outdoor plants
Overwatering
ModerateLeaves droop but feel firm and swollen. Growth slows, and lower leaves may yellow and drop. Can lead to root problems.
- Leaves drooping uniformly but feeling firm (not wilted)
- Slow, stunted growth
- Lower leaves yellowing and potentially dropping
- Algae formation on soil surface
- Soft, waterlogged stems near base
- Watering too frequently before medium dries adequately
- Poor drainage in containers
- Using soil with poor drainage properties
- Containers without adequate drainage holes
- Saucers remaining full of water beneath pots
- Allow growing medium to dry until top 2-3cm feels dry
- Lift pots to judge weight - light means need water, heavy means still wet
- Improve drainage by adding perlite to soil mix
- Consider using fabric pots for better aeration
- Water less frequently but more thoroughly when you do water
- Empty saucers after watering to prevent roots sitting in water
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Prevention Guide
The best way to deal with cannabis problems is to prevent them. Follow these best practices to maintain healthy plants and minimize issues.
Environment Control
- Maintain temperature between 20-28°C (68-82°F)
- Keep humidity 40-60% during vegetative growth, 40-50% during flowering
- Ensure adequate air circulation with oscillating fans
- Provide proper light intensity and schedule
- Clean growing area regularly to prevent pest habitats
Nutrition Management
- Follow feeding schedules appropriate for your growing medium
- Start with 1/4 to 1/2 strength nutrients for young plants
- Maintain proper pH: 6.0-6.5 for soil, 5.5-6.0 for hydroponics
- Allow 10-20% runoff when feeding to prevent salt buildup
- Flush growing medium every 2-3 weeks to reset nutrient balance
Watering Practices
- Allow soil to dry out slightly between waterings
- Water thoroughly until you see runoff, then stop
- Water at the base of plants, avoiding leaves when possible
- Use room temperature water to prevent root shock
- Adjust watering frequency based on environment and plant size
Pest & Disease Prevention
- Quarantine new plants for 1-2 weeks before introducing them
- Regularly inspect plants, especially leaf undersides
- Consider preventative beneficial insects like predatory mites
- Keep growing area clean and free of debris
- Use sticky traps to monitor for flying insects
Need Personalized Diagnosis?
For issues that are difficult to identify or require tailored solutions, our AI Herbal Advisor can help. Upload photos of your plants and get immediate, personalized guidance.
- Upload photos directly from your device
- Get accurate visual analysis of plant problems
- Receive customized treatment recommendations
- Track problem progression and resolution
- Available 24/7 for immediate assistance