Optimise the vegetative phase: Maximise growth

The vegetative phase largely determines the final size and structure of cannabis plants:

**Vegetative phase basics:**

*Duration of the vegetative phase:*

- Photoperiod varieties: 4-8 weeks

- Depending on the desired plant size

- Indoor usually shorter than outdoor

- Strain-specific differences

- Take space restrictions into account

*Physiological processes:*

- Intensive cell division and elongation

- Build-up of leaf mass for photosynthesis

- Development of the root system

- Stem and branch thickening

- Energy storage for the flowering phase

**Optimal light conditions:**

*Vegetative light cycles:*

- 18/6 standard (18h light, 6h darkness)

- 20/4 for accelerated growth

- 24/0 possible but energy-intensive

- Constant cycles important

- Timer precision required

*Light intensity:*

- PPFD 400-600 µmol/m²/s optimal

- DLI 25-40 mol/m²/day

- Gradually increase from 300 to 600

- Avoid light burn

- Uniform illumination

*Spectrum for vegetative growth:*

- Blue-emphasised spectrum (400-500nm)

- Promotes compact, bushy growth

- Full spectrum LEDs optimal

- 6500K colour temperature with CFL

- UV-A additive for stress resistance

**Nutrient management vegetative:**

*NPK ratio vegetative:*

- Nitrogen-emphasised (3-1-2 or 2-1-1)

- High N values for leaf growth

- Moderate P and K values

- Calcium and magnesium important

- Do not neglect micronutrients

*Feeding schedule vegetative:*

- Week 1-2: EC 0.8-1.0

- Week 3-4: EC 1.0-1.4

- Week 5+: EC 1.4-1.8

- pH 6.0-6.5 (soil) / 5.5-6.0 (hydro)

- Regular flushing every 2-3 weeks

*Organic fertilisation vegetative:*

- Nitrogen-rich organic fertilisers

- Blood meal, fish emulsion

- Compost tea weekly

- Kelp meal for trace elements

- Molasses for soil microbes

**Environmental optimisation:**

*Vegetative temperature:*

- Day: 22-26°C optimal

- Night: 18-22°C

- Temperature difference should not exceed 10°C

- Aim for constant values

- Air circulation for homogeneity

*Humidity vegetative:*

- 60-70% RH optimal

- Higher values than in flowering

- Good air circulation nevertheless important

- VPD 0.8-1.2 kPa

- Gradual reduction during flowering

**Training in vegetative phase:**

*LST (Low Stress Training):*

- Continuous gentle bending

- Promote horizontal spread

- More light for all shoots

- Daily small adjustments

- Prepare structure for SCROG

*Topping and FIM:*

- Possible after 4-6 nodes

- At least 2 weeks before flowering change

- Doubles number of main shoots

- Requires recovery time

- Only for healthy plants

*Defoliation:*

- Selective removal of large leaves

- Improved air circulation

- More light for lower areas

- No more than 20% at a time

- allow 1-2 weeks recovery

**Growth monitoring:**

*Development indicators:*

- Daily height increase

- New nodes formation

- Leaf size and colour

- Stem thickening

- General vigour

*Recognise problems early:*

- Discolouration or spots

- Growth arrest

- Pest infestation

- Nutrient deficiencies or excess