Full spectrum LED: Why the light spectrum is crucial

The light spectrum determines the growth quality and cannabinoid development in cannabis:

**Why full spectrum is important:**

Cannabis utilises different light ranges for different processes. Mono-spectrum LEDs (blue/red only) can be used for growth, but full-spectrum LEDs optimally simulate natural sunlight.

**Spectrum ranges and their functions:**

*UV range (280-400nm):*

- UV-B (280-315nm): Increases THC and terpene production

- UV-A (315-400nm): Promotes compact growth

- Caution: Too much UV can burn leaves

- Dosage: 1-2% of the total output

*Blue range (400-490nm):*

- Promotes vegetative growth

- Prevents elongation (internode spacing)

- Important for chlorophyll development

- Optimal: 15-25% of the spectrum

*Green range (490-580nm):*

- Long underestimated - important for light penetration

- Reaches deeper leaf layers

- Supports photosynthesis in dense canopy

- Optimal: 15-25% of the spectrum

*Red range (580-700nm):*

- Main driver for flower development

- Maximises biomass build-up

- Influences elongation in the flower

- Optimal: 35-45% of the spectrum

*Dark red/infrared (700-800nm):*

- Supports flower maturity

- Influences morphology

- Important for Emerson effect

- Optimal: 5-10% of the spectrum

**Adjust spectrum according to growth phase:**

*Seedlings (0-2 weeks):*

- Higher blue component (30-40%)

- Lower intensity (100-300 PPFD)

- Minimal UV (plant protection)

*Vegetative phase:*

- Balanced blue-green-red (25-25-40%)

- Medium intensity (300-600 PPFD)

- Light UV for compactness

*Flowering phase:*

- Increased red content (40-50%)

- Maximum intensity (600-1000 PPFD)

- UV boost for trichome development

**Recognise quality LEDs:**

*Samsung LM301H/LM301B:*

- Industry standard for efficiency

- Outstanding spectrum quality

- Long lifetime (50,000+ hours)

*Osram/Lumileds chips:*

- Premium alternative to Samsung

- Often used in high-end panels

- Excellent colour rendering

*Avoid no-name LEDs:*

- Poor spectrum quality

- High failure rate

- Exaggerated wattage specifications

**Spectrometer measurements:**

Professional growers measure the actual spectrum of their LEDs:

- Par meter for PPFD measurement

- Spectrometer for spectrum analysis

- Apps are inaccurate, prefer hardware measuring devices

**Frequent spectrum errors:**

*Too much blue:*

- Plants growing stunted

- Very dark leaves

- Reduced elongation also in flower

*Too much red:*

- Excessive elongation

- Thin, weak stems

- Light-hungry plants

*No UV:*

- Lower trichome density

- Less intense flavours

- Lower cannabinoid levels

**DIY spectrum tuning:**

Advanced growers can customise their spectrum with separate LED strips:

- UV-A/UV-B strips for trichome boost

- Dark red LEDs for flower enhancement

- Separate dimmers for phase adjustment