CO2 supplementation: maximising photosynthesis

CO2 supplementation is an advanced technique for maximising the rate of photosynthesis:

**CO2 and photosynthesis:**

*Natural CO2 levels:*

- Outdoor air: 400-420 ppm

- Optimal cannabis values: 1200-1500 ppm

- Absolute upper limit: 2000 ppm

- Dangerous for humans: >5000 ppm

*Photosynthesis enhancement:*

- More CO2 = more plant growth

- Only effective with sufficient light

- Temperature-dependent efficiency

- Nutrient requirements increase

**CO2 sources:**

*CO2 bottles:*

- Precise dosing possible

- Consistent supply

- High acquisition costs

- Maintenance and refilling necessary

*CO2 generators (propane/butane):*

- Cost-effective production

- Also generates heat

- Moisture as a by-product

- Combustion gases are produced

*Fermentation (DIY):*

- Yeast + sugar solution

- Very inexpensive

- Irregular production

- Difficult to control

*Dry ice:*

- Immediate release of CO2

- Difficult to dose

- Short duration of action

- Cooling as a side effect

**Equipment and installation:**

*CO2 controller:*

- Automatic control

- PPM measurement and control

- Timer functions

- Safety features

*Distribution system:*

- Perforated hoses

- Strategic placement

- Even distribution

- Consider air circulation

*Monitoring:*

- PPM measuring devices

- Continuous monitoring

- Alarm functions

- Data recording

**Timing and dosing:**

*Light ON phase:*

- CO2 only when light is switched on

- Photosynthesis-dependent

- Waste in the dark

- Timer control important

*Daily cycle:*

- Morning: 1200-1500 ppm

- Midday: utilise peak times

- Evening: Reduction before lights switch OFF

- At night: Switch off completely

*Growth phases:*

- Germination: No CO2 required

- Vegetative: 1000-1200 ppm

- Flowering: 1200-1500 ppm

- Last 2 weeks: Reduction

**Environmental optimisation:**

*Temperature adjustment:*

- With CO2: 25-30°C optimal

- Without CO2: 20-25°C optimal

- Higher temperatures tolerable

- Air conditioning often necessary

*Humidity:*

- Lower RH with high CO2

- Vegetative: 50-60% instead of 60-70%

- Flowering: 40-50% instead of 50-60%

- Dehumidification more important

*Lighting:*

- More light possible with CO2

- 600-1000 µmol/s/m² optimal

- LED full spectrum preferred

- Heat management important

**Nutrient adaptation:**

*Increased demand:*

- 20-30% more nutrients

- Calcium and magnesium critical

- Potassium for CO2 utilisation

- pH stability more important

*Irrigation:*

- More frequent watering

- Increased water requirement

- Adjust EC values accordingly

- Check drainage

**Safety:**

*Human health:*

- Never >2000 ppm in occupied spaces

- Install CO2 warning systems

- Ensure good ventilation

- Regular monitoring

*Room sealing:*

- Minimise CO2 losses

- Ventilation only when necessary

- Aim for a closed system

- Identify and seal leaks

*Emergency procedure:*

- Immediate ventilation in case of overdosing

- Automatic shutdown

- Access to fresh air

- First aid knowledge

**Cost-benefit analysis

*Acquisition costs:*

- CO2 system: 300-150