Successful flowering phase management for maximum potency and yields. Perfectly harmonise nutrients, environment and timing.
The flowering phase requires precise management for optimum results:
Understanding flowering phase stages:
Pre-flower (week 1-2):
- First signs of sexing
- Internode elongation begins
- Hormonal change
- Nutrient adjustment necessary
- Training still possible
Early Flower (week 3-4):
- Stretch phase fully developed
- First real flower formation
- Height increase 50-200%
- Structure finalised
- No more training
Mid Flower (week 5-7):
- Intensive flower development
- Maximum nutrient demand
- Resin production increases
- Weight gain of buds
- Optimum environmental control critical
Late Flower (week 8+):
- Flower maturation
- Trichome development
- Nutrient reduction
- Start flushing
- Harvest preparation
Lighting for flowering phase:
12/12 light cycles:
- Absolute darkness required
- Do not tolerate light leaks
- Timer precision critical
- Maintain constant times
- Avoid interruptions
Light intensity flowering:
- PPFD 600-1000 µmol/m²/s
- DLI 35-50 mol/m²/day
- Gradually increase over weeks
- Maximum in mid-flower
- Reduction before harvest optional
Spectrum for flowering:
- Red-emphasised spectrum (660-730nm)
- Promotes flower development
- Far-red for stretch control
- Full spectrum still optimal
- 2700K for HPS/CFL
Flower nutrient management:
Flowering NPK ratio:
- Phosphorus-emphasised (1-3-2)
- Reduced nitrogen
- Increased potassium
- Calcium/magnesium constant
- Micronutrients important
Feeding schedule flowering:
- Week 1-2: Transition nutrients
- Week 3-6: Full flowering dose
- Week 7+: Start reduction
- Last 1-2 weeks: Flush
- Adjust EC values accordingly
Special bloom additives:
- PK booster (phosphorus/potassium)
- Molasses for microbes
- Cal-Mag Supplements
- Silicon for structure
- Enzymes for root health
Environmental control flowering:
Flowering temperature:
- Day: 20-26°C (cooler than Vegi)
- Night: 16-20°C
- Temperature difference important
- Cooler nights promote colour development
- Avoid heat stress
Flowering humidity:
- Early Flower: 55-65% RH
- Mid Flower: 45-55% RH
- Late Flower: 40-50% RH
- Mould prevention is a priority
- Increase air circulation
VPD management:
- Optimal: 1.0-1.5 kPa
- Higher VPD than vegetative
- Promote transpiration
- Optimise nutrient transport
- Find stress balance
Stretch management:
Stretch factors:
- Genetics (Sativa > Indica)
- Light intensity and spectrum
- Temperature difference day/night
- Nutrient availability
- Training history
Stretch control:
- Increase light intensity
- Keep temperatures more constant
- Training in Pre-Flower
- Use SCROG nets
- Supercropping as an emergency
**Promote flower development
Environmental optimisation:
- Constant 12/12 cycles
- Optimum temperature/humidity
- Adequate air circulation
- Maintain CO2 levels
- Eliminate stress factors
Nutrient timing:
- Timely switch to flowering fertiliser
- PK boost in mid-flower
- Cal-Mag throughout
- Don't forget micronutrients