LED lighting has become popular in recent years for indoor cannabis cultivation. It offers an efficient light source that saves energy, reduces heat, and allows the spectrum to be adjusted to different growth stages.
- Benefits of LED lighting
Energy efficiency: LEDs consume much less electricity than HPS or MH lamps.
Cooler temperature: less heat production reduces the chance of heat stress.
Adjustable Spectrum: Some LEDs can change the light spectrum for vegetative growth or flowering.
Long life: LED lamps often last more than 50,000 hours.
Compact setup: ideal for small grow rooms or tents.
- Light requirements for cannabis under LED
Vegetative stage: 18–24 hours of light per day, ideally with a bluish spectrum (450–500 nm) for leaf and stem development.
Flowering phase: 12 hours light and 12 hours dark, red spectrum (620–660 nm) stimulates flower development.
Light intensity: average 400–600 µmol/m²/s for vegetative stage, 600–900 µmol/m²/s for flowering.
LEDs can be placed close to plants for low heat output, but pay attention to light intensity to avoid leaf burn.
- Distance to plants
Small LED panels (100–200 W): 30–50 cm above the tops.
Larger LEDs (400–600 W): 50–80 cm distance.
High intensity LEDs (>1000 W): 80–120 cm, depending on manufacturer and light distribution.
Tip: Observe the plants; leaves that curl or turn white can indicate too much light.
- Food and water under LED
LED lighting often promotes faster photosynthesis, meaning plants require more nutrients than with conventional lights.
Check the pH and EC of water and nutrients regularly.
Start with lower doses of food for young seedlings and gradually increase during the vegetative stage.
- Environmental factors
Temperature: 20–28°C ideal, LEDs produce less heat, but ventilation remains important.
Humidity: 50–70% in vegetative stage, 40–50% in flowering to prevent mold.
Ventilation: continuous air circulation strengthens stems and prevents overheating.
- Common mistakes
Too close to the lamps: leaf burn or light stress.
Insufficient ventilation: heat build-up and mold problems.
Insufficient nutrition: Faster photosynthesis requires sufficient macro and micronutrients.
Ignoring spectrum: Some cheap LEDs don't have an adjusted spectrum, which can affect flowering and yield.