Understanding the natural growth cycle of cannabis and the attendant light cycle and spectrum needs is fundamental to growing a great product indoors.
Cannabis is a photosensitive plant meaning that the amount of light it is exposed to within a 24 hour period will trigger responses in the plant. Your light selection and schedule is critical to the growth of your plant.
Manipulating Cannabis Growth with Light
Different wavelengths of light affect your plants depending on the growth cycle stage. Light spectrum also affects plant growth differently depending on things like environmental conditions and crop performance.
Exposing your plants to specific hours of light and dark in conjunction with a proper photosynthetic active radiation (PAR) light spectrum at a particular growth stage can ignite growth. By manipulating your cannabis light cycle, you can yield growth before the flowering stage in particular. This correlates to improved quality and yields for end-use products.
Stages of the Cannabis Growth Cycle
The cannabis growth cycle is categorized into 4 distinct stages: germination, seedling, vegetative, and flowering. It is important to understand the indoor cannabis light cycle, so you can choose the correct grow light and spectrum for each stage. BIOS also offers broad-spectrum fixtures that can be used across the full cycle with adjustments to schedules and intensities.
Understanding the light cycles will allow you to plan your grow room properly. Let’s explore the four light stages for growing cannabis, weed, or pot in depth below.
1. Propagation
The germination stage is the first stage in the cannabis plant cycle and can last anywhere between 5 to 10 days. Clones are established in just a few days, while cannabis seeds may sprout between 2 and 10 days.
During this critical time, it is important to follow a routine light cycle when growing indoors. Your plants need plenty of light in this stage; typically, 16 hours of light and 8 hours of darkness.
Although the propagation stage with both seeds or clones is less significantly affected by wavelengths when compared to the vegetative and flowering stage, it is still important to use the correct spectrum of light during this phase, which is typically broad spectrum to promote and establish healthy plants.
2. Clone or Seedling
After the clones or young plants are transferred to a new container, they will spend the next 2-3 weeks in the delicate growth stage. After propagation, the plant is primed to begin developing its root system, as it will require an ever-growing network of nourishment.
As it begins growing in search of nutrients, the young plant will begin to produce sets of leaves. Initially, you may observe sets of 2 or 3, and then 5 or 7 as it progresses. During this stage, the plant needs fewer soil nutrients and less water than in the final two growth stages.
A common mistake growers make during this clone or seedling stage is overfeeding the plant. While usually done with good intentions, this can result in stunted growth and lower yields. The light cycle during this phase is a recommended light for 18 hours a day and 6 hours of darkness, mimicking an exceptionally long summer day.
A broad-spectrum LED with some blue wavelengths is optimal for the first 10–14 days and will help develop healthier leaves. Once the marijuana plants have developed healthy leaves and at least 3 nodes, they move into the vegetative stage.
3. Vegetative
The vegetative light cycle of cannabis is when plant growth truly takes off. Much like a human adolescent, the plant will achieve most of its vertical growth during this time. Lasting between 3 to 6 weeks, the vegetative stage requires broad-spectrum light for 18 hours and 6 hours of darkness.
Some argue for 24-hour light cycles during this stage, but that choice may lead to nutritional deficiencies and stunted growth in the final flowering stage. The time spent in darkness enables cannabis plants to translocate nutrients and energy stored in the form of sugars and then prepare themselves for another day of growth.
During this stage, the roots and foliage of your cannabis plants can develop rapidly. You can achieve this using a broad spectrum grow light.
Dimming controls enable you to adjust light schedules and intensities (from 0 to 10V) to ensure your BIOS grow lights deliver exceptional light output and uniformity. The BIOS broad spectrum is engineered to maximize photosynthesis and growth.
4. Flowering
The flowering stage is often the most exciting stage for most growers as they see and smell the results of their hard work. For your plants to reach their full potential, you will transition your plants from a veg cycle to a flowering light cycle with 12 hours of light and 12 hours of darkness.
Depending on the strain, this cycle lasts between 8 to 11 weeks. It should also be noted that during the transitioning period between the vegetative and flowering stages, the plant will begin to produce a distinct odor and sticky buds.
This cycle is mimicking the sun’s natural exposure and cycle during the transition experienced in fall. During this time the plants’ buds will grow in size, the pistils will darken, and trichomes will become whiter.
Light spectrums during the flowering stage
The use of a broad spectrum is incredibly effective at this time. BIOS indoor cannabis cultivation light fixtures remain one of the best solutions for growers to imitate the shallow angle of the sun in late summer and autumn, resulting in denser more resinous buds and accelerated growth.
While some growers contend that red wavelength ratios become important during the flowering stage, red light tends to stretch bud formation and make for airy and not as dense buds. UV lighting may be effective at boosting THC, but could also create risks for human and plant health
Commercial LED lighting for cannabis cultivation
When it comes to lighting, spectrum choice matters, and at BIOS, we strive to learn more about it every single day.
As evidenced by our customer success, BIOS broad spectrum and PAR focus provide commercial growers with grow light options to get the precise spectrum that our plants need.
