💡 Light Management & Calculations
Proper lighting is crucial for healthy plant development. Understanding light cycles and intensity helps optimize growth at each stage.
📅 Light Cycles (Photoperiodism)
Cannabis is a photoperiod-dependent plant, meaning its life cycle stages are triggered by changes in light duration.
- Vegetative Growth (18-24 hours light): Long light periods signal the plant to focus on developing leaves and stems.
- Flowering (12 hours light, 12 hours darkness): A reduction to 12 hours of uninterrupted darkness signals the plant to produce flowers.
⚠️ Light Stress Symptoms
- Over-Lighting: Leaves curl upwards (tacoing), yellowing/bleaching of top leaves, stunted growth.
- Light Burn: Crispy/burnt tips, white patches on leaves closest to light.
- Under-Lighting: Stretching (long internodal spacing), pale green leaves, slow growth.
🔢 Basic Light Calculations
A general rule of thumb for LED lighting:
- Seedling: 15-25 watts per sq ft
- Vegetative: 25-35 watts per sq ft
- Flowering: 35-50+ watts per sq ft
🎯 Transition Tips: When switching to 12/12 for flowering, ensure the dark period is truly uninterrupted. Even small light leaks can confuse the plant and cause stress.