Photosynthesis is the process of a plant capturing light energy to create chemical energy as a food source. Photons are the smallest unit of electromagnetic radiation absorbed by the plant’s chloroplast to form chemical molecules that convert minerals, carbon dioxide (CO2), and water(H2O)into carbohydrates and sugars as stored energy in glucose molecules. When choosing a light source for an indoor or mixed-light garden, photons delivered to the canopy in the most efficient manner is the core metric. Photons emitted by Metal Halide (MH), High Pressure Sodium (HPS), or Light Emitting Diodes (LED) are all sufficient sources, but wavelengths and angles will vary. While plants are indifferent to light technology, they do benefit from optimized spectrum balance, intensity, and photon distribution.

PPF stands for photosynthetic photon flux, which is the total number of photons that are released from the light source. PPFD is the photosynthetic photon flux density of the number of photons, measured in micromoles (one micromole equals 62 quadrillion photons) per square meter per second, that land on a particular area, surface or plant canopy. Reducing watts while still increasing PPFD and being able to balance power capabilities with low production cost and high total numbers of grams per square footage output in yield, is a constant factor and challenge for every indoor and mixed-light cannabis cultivator.

Light spectra is an essential factor in plant growth rates and health. Full and mixed-spectrum provide plants with a balance of cool and warm light designed to imitate the natural white solar rays. Peak photosynthetic rates occur in the red light and blue light spectrums. Blue light radiation is considered to be favorable for structural development during the vegetative growth stage by reducing stem elongation and promoting rapid leaf growth. Red light radiation has proven most efficient in the flowering stage as a contributing element to greater trichome production and blooming bud density.