LED lighting in a cannabis grow room improves plant health and yield, but which lights work best for each stage of growth? From cool blue and green colors to bold red lighting, various wavelengths encourage plant growth in different ways. Learn more about which colored lights help cannabis plants grow and how you can incorporate the lights into a grow room.
Blue Light
Blue light improves the vegetative stage of cannabis growth. It encourages bushy plant structure and robust leaf development.
Blue wavelengths (400-500 nanometers) support strong stem growth and help stomata open wide. Therefore, more carbon dioxide fuels photosynthesis for cannabis. Use LED grow lights with a high blue light spectrum during this phase for lush, vibrant plants.
Red Light
For the flowering stage, use red light to increase bud production. Between 600 and 700 nanometers, these wavelengths stimulate the plant’s flowering hormones.
Cannabis exposed to ample red light produces a higher quantity and quality of flowers. For best results, shift the light setup to include more red-spectrum LEDs or high-pressure sodium (HPS) grow lights as cannabis plants transition to the flowering stage.
Far-Red Light
Far-red light exists on the periphery of the light spectrum (700-800 nanometers) and helps the plant with flowering. This spectrum can trigger the shade-avoidance response, which causes the plant to stretch and produce larger buds.
Although powerful, only use far-red light sparingly in combination with a red spectrum. This way, you can prevent overstretching the plant.
Green Light
While growers may overlook green light, it’s the ideal wavelength—between 500 and 600 nanometers—to deeply penetrate the plant canopy. Multitiered growing setups commonly benefit from green lights because they provide additional energy for shaded areas.
Low levels of green-colored light also help cannabis plants grow by increasing photosynthesis. Incorporate a balanced proportion within the light spectrum to evenly distribute light through the canopy.
UV Light
Using ultraviolet (UV) light increases tetrahydrocannabinol (THC) levels in cannabis plants. By simulating natural sunlight, adding UV light can mimic stressful conditions and prompt the plant to produce more resin as a protective measure.
However, too much UV light can be harmful. It could burn the leaves or hinder the plants’s development. To regulate UV light, use LED grow lights to save energy and monitor your garden to maximize cannabis growth.
Take advantage of colored light to stimulate growth for your cannabis plants. As they progress through their lifecycle, switch out and combine these colors for the best results. Experiment with different light levels to grow a healthy harvest.