Genetics, soil, and light distribution are the three fundamental elements for growing excellent cannabis plants. In contrast to plant genetics or soil, light can be easily controlled using light-dark cycles, allowing the plant to develop according to the hours of light exposure.
Without enough light, the plant cannot reach its full potential. Although a plant may grow in a low-light environment, no flowers of acceptable quality will be produced. Cannabis is a plant species that requires quite a lot of light to produce a good quantity of flowers. The life cycle of cannabis is conditioned by photoperiodism. To better understand this concept, we can say that each plant carries an internal clock that counts light and dark hours to determine when to start growing and flowering.
Autoflowering vs Photoperiod Cannabis: Light and Darkness
Unlike photoperiod cannabis plants, autoflowering cannabis strains are not dependent on a specific photoperiod, as they can obtain carbon dioxide (CO2) during daytime—so no darkness is needed. In order to achieve maximum yield, many growers insist on growing autoflower varieties under continuous light—24 hours a day—to make the most of this special ability to flourish irrespective of light and dark hours.
A photoperiod is the number of hours each day during which a plant is exposed to light and darkness. This is usually expressed using two numbers—e.g., 18/6, to indicate 18 hours of light and 6 hours of darkness. When plants are grown outdoors, the number of light hours depends on the month of the year. In the case of indoor growing, the photoperiod is adjusted using a timer that turns lamps on and off—so that the photoperiod is programmed.
In this way, when light hours exceed 14 hours each day, the plant remains in its growing stage—also called vegetative growth stage. If a plant receives less than 13 hours of light a day, the plant will continue into its flowering stage. If a plant has begun its flowering stage and light hours increase over 13 hours a day, the plant may stop flowering and start its growing stage again (re-vegging). A photoperiod of less than 12 hours will accelerate the flowering stage but will also reduce production. During dark hours, we must make sure that plants are in complete darkness, so that they flourish, because just a glimmer of light in the dark will hinder proper flowering.
Some growers use green light to work on their indoor gardens during the night so that plants do not receive excessive light. If a plant is illuminated—even for just a few seconds—during its dark hours, a mutation may occur, turning plants into hermaphrodites. When this happens, plants start budding male flowers which pollinate females, producing a large number of seeds.
Solar Light vs Artificial Light
If we are to simulate solar light for indoor growing or in a greenhouse, we must bear in mind that the light spectrum depends on the type of lamp used. The spectrum indicates the distribution of light waves at different frequencies—light travels at visible, ultraviolet and infrared frequencies. Lightbulbs or halogen lamps used at homes have been designed to produce the greatest amount of power at wavelengths that are visible to the human eye. Lamps for growing are designed to produce the largest amount of brightness with the lowest possible level of consumption, which is why they are the most efficient as to illumination. Lamps must be placed at a reasonable distance to avoid burning plants.
Cannabis growing demands patience, since harvesting before the plants are ready will result in a lot of chlorophyll and little THC. Late harvest, on the other hand, translates into plants with narcotic features that may produce undesired effects. Light overexposure or inadequate illumination may cause stress, so plants will produce seeds instead of flowers. Irrespective of the source of light, what matters the most is knowing about cannabis cycles and the needs of the plant according to each growing stage.