Healthy roots are crucial for vigorous growth. Root care, problem detection and treatment for optimum results.
Root health is the foundation for successful cannabis cultivation:
Root zone basics:
Root functions:
- Nutrient uptake from substrate
- Water uptake and transport
- Oxygen supply to the plant
- Stability and anchoring
- Hormone production
Healthy root characteristics:
- White to cream colour
- Firm, fleshy structure
- Pleasant, earthy odour
- Strong branching
- Active growth
Sick root signs:
- Brown or black discolouration
- Slimy, soft texture
- Foul odour
- Little branching
- Stagnant growth
Root care in various media:
Soil:
- Drainage crucial
- Airy substrate mix
- Moderate moisture
- Organic matter beneficial
- Utilise mycorrhizal symbiosis
Coco:
- More frequent watering
- Supplement Cal-Mag
- pH stability important
- Avoid salt build-up
- Regular irrigation
Hydro:
- Water closure is critical
- Continuous aeration
- Temperature control
- Sterile conditions
- Nutrient solution change
Oxygen supply:
Why oxygen is critical:
- Enable root respiration
- Prevent anaerobic bacteria
- Optimise nutrient uptake
- Avoid root rot
- Promote a healthy microbiome
Aeration methods:
- Drainage layer in pots
- Perlite in the substrate
- Air stones in Hydro
- Fabric Pots
- Optimise substrate choice
Avoid overwatering:
- Use finger test
- Check pot weight
- Monitor drainage
- Adjust watering intervals
- Never leave the root zone permanently wet
Temperature management:
Optimal root temperatures:
- Soil: 18-22°C
- Coco: 19-23°C
- Hydro: 18-20°C
- DWC: 16-20°C (cooler due to oxygen)
Temperature control:
- Insulate reservoirs
- Chiller for hydro systems
- Pot insulation for extreme temperatures
- Heating mats for cold environments
- Use substrate thermometers
Nutrient optimisation:
Root Zone pH:
- Soil: 6.0-7.0
- Coco: 5.8-6.2
- Hydro: 5.5-6.0
- Measure and adjust regularly
- minimise pH fluctuations
EC management:
- Avoid over-fertilisation
- Prevent salt build-up
- Flushing in case of problems
- Check run-off EC
- Gradual adjustment
Beneficial Supplements:
- Mycorrhizal Fungi
- Beneficial Bacteria
- Fulvic/Humic Acids
- Vitamin B1 (Thiamine)
- Seaweed extracts
Recognising root problems:
Pythium (root rot):
- Brown, slimy roots
- Foul odour
- Wilting leaves despite moist substrate
- Slow growth
- Immediate treatment necessary
Root bound (pot too small):
- Roots grow in circles
- Very rapid drying out
- Slowed growth
- Nutrient deficiencies
- Repotting necessary
Nutrient burn on roots:
- Brown root tips
- Overfertilisation as cause
- EC values too high
- Rinsing with pH-corrected water
- Reduce fertiliser concentration
Treatment of root problems:
Pythium treatment:
- Remove affected roots
- H2O2 rinse (3% solution)
- Add beneficial bacteria
- Optimise environment