Cannabis plants are highly sensitive to light cycles and exposure. This sensitivity makes it possible for growers to control light cycles that encourage increased vegetation or flowering, and maximize marijuana yields.
Each plant type is different in its response to light. But in general, the growth characteristics of each crop are triggered by specific light spectrums throughout the daylight cycle.
Vegetative
When growing cannabis plants, you must understand the impact that different types of light have on their growth and yield. While some types of light can help your cannabis grow strong, healthy roots and stems, other types of light can stunt your plants’ development or cause them to produce low-quality flowers.
The impact of different types of light on cannabis production is based on the plant’s stage of growth, the time it is growing, and the environment that is surrounding it. This means that you should monitor the type of lights you are using, as well as how closely they are hanging to your plants’ canopy.
Vegetative cannabis growers typically use LEDs, as these are more energy efficient than other lighting options and can provide a wide range of lighting spectrums. It is important to choose the right spectrum of LEDs for the specific stages of your cannabis production.
Blue wavelengths in the 400-500 nm range are ideal for the vegetative phase of cannabis plants. This light helps plants develop robust, resilient, and broad leaves that can withstand the stresses of flowering. It also helps them metabolize the nutrients in their soil more efficiently.
However, too much blue light can result in a lanky plant with small leaves and stems. You can counteract this effect by lowering the intensity of the blue light you are using to ensure that the plants get enough airflow through their leaves.
Some cannabis growers also use red light, as this can promote the development of flowers and buds. This light can also boost the amount of terpenes produced by your cannabis plants.
This light can suppress a number of pathogens, including downy mildew and powdery mildew. This can be a great way to protect your plants against disease, but it is important to note that too much of this light can negatively impact your cannabis yield.
The impact of varying light spectra on cannabis production can be quite dramatic, as it highly influences plant morphology and key secondary metabolite profiles. This study explored the effects of six light spectra on C. sativa (‘Babbas Erkle Cookies’ accession) growth traits, terpene production, and operational costs.
To evaluate the influence of the different light spectra, cannabis clones were cultivated under high-pressure sodium (HPS), amber-rich AP673L LED, and NS1 LED at light intensity of
Cannabinoid (CBG) and total terpene yield per plant were greatest under HPS light (0.029 +- 0.003 g plant-1), followed by purple, rose, amber, and blue (0.024 +- 0.002 g plant-1). Conclusion: These results suggest that a dichromatic LED light might be the best solution to balance out the deleterious effects of pure blue light on growth traits while maintaining secondary metabolite levels comparable to conventional HPS lighting.
Flowering
While cannabis plants are primarily influenced by light intensity, the spectrum of light is also important. For instance, red light stimulates the production of terpenes and a higher proportion of the plant’s photosynthesis is conducted under a red-light spectrum.
During flowering, the amount of red light your cannabis plants receive will have a significant impact on their growth and yields. The type of lights you use will play an important role as well, with metal halide and High-Pressure Sodium (HPS) grow lights being the most effective at this stage.
As a rule of thumb, you should replace your bulbs on a regular basis to ensure the best possible results and that your plants are getting the maximum number of PPFDs they need to thrive. In general, you should aim to maintain your plants’ PPFDs between 400 and 450 mmol m-2 s-1 for the flowering phase.
When growing cannabis indoors, it is crucial to have a consistent light cycle of 16 hours of light and 8 hours of darkness per day. This is the best way to ensure that your plants are receiving adequate levels of red and amber light, which will help them reach their full height and produce more buds.
The length of time a cannabis plant spends in the pre-flowering stage is dependent on a variety of factors, including genetics and grow conditions. Autoflowering strains tend to be ready to flower within a week or two, while photoperiodic varieties will typically take longer to reach the flowering stage.
Once your plants enter the flowering stage, it is a good idea to make sure that they are given plenty of phosphorus and potassium. This will encourage the development of strong trichomes and increase the size of your buds. The blooming stage is also a great time to add flower boosters, which will also provide additional levels of these essential nutrients for your plants.
In some cases, your flowers can also be sprayed with a fungicide during this phase of the cannabis crop’s lifecycle to prevent diseases and other pests from affecting their quality and production. There are several different types of fungicides available, and many are specifically designed for the specific needs of marijuana cultivation.
For instance, the fungicide Phytothiosan has been shown to have an additive effect on trichome production in cannabis plants and to reduce the number of bugs that cause problems for your plants. You should consider adding a fungicide to your routine as it can greatly improve the quality and yield of your harvest.
As with all stages of a cannabis plant’s life cycle, the time it takes to flower will depend on a variety of factors, but mainly on genetics and your growing environment. Generally, it will take between 5 and 10 weeks to fully mature outdoor plants and around 4 weeks for indoor ones.
Harvest
When it comes to harvest time, a grower should pay attention to the impact of different types of light on their cannabis plants. It is crucial that they use the correct spectrum at the right time to ensure their plants get the best possible results.
The color of the light you choose will affect a number of factors including how long your plants stay in vegetative and flowering phases, how many flowers they produce, and their overall yield. Ideally, you should use metal halide lights during the growth phase and HPS lights during flowering to ensure the best results from your growing operation.
Metal halide grow lights, which have an intensity of up to 1000 watts, are perfect for the vegetative stage of your plant’s growth cycle. The 660nm wavelength of light that metal halide emits falls into the perfect range of the color spectrum for a vegetative Cannabis plant.
Red is another color of light that has a great effect on the growth and development of cannabis plants. It stimulates the synthesis of chlorophyll, which helps the plants absorb and process sunlight into energy to help them grow.
It also encourages stem cells to produce more leaves and longer roots, which makes it easier for your plant to grow large and healthy. However, too much red light can lead to your plant becoming overgrown and elongated, which can result in less yields.
Using LEDs in your grow room is the latest trend in the industry and they are fast becoming a popular choice for growers. They are far more efficient than other types of lights and are kinder to the environment as well as your electricity bill.
You can also get special horticultural LEDs that have been designed specifically for the needs of growing cannabis. These lights are effective at maximizing yields and cannabinoid concentrations in your plant. They also allow you to change the spectrum of light for each growth stage, which will improve the quality and yield of your crop.
Some high-end LEDs are even designed for a dual-purpose, meaning you can switch between a blue or green spectrum for vegetative growth and then use a red or yellow spectrum for flowering. This will allow you to maximize the yield of your crop without sacrificing the quality and flavor of your crop.
If you are planning on using LEDs, you should know that some growers have reported a significant increase in their yields. This is because the LEDs are more efficient and run cooler than traditional HIDs.
To prevent light loss from the lighting you are using, it is essential to install reflectors near your lights. Having these reflects will help ensure that every little bit of light gets to your plants.
In addition to the light you use, how you set up your grow room is another important factor. Having the proper spacing between the lights will have a big impact on the overall production of your crop. Typically, you want your lights to be about 5 cm away from your Cannabis plants.
