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Autoflowers are one of the most popular types of cannabis plants, due to their ease of growth and their short life cycle. However, growing autoflowers can be a bit tricky, especially if you are new to growing cannabis.
One of the most important factors to consider when growing autoflowers is the amount of light they receive, and specifically the PAR, DLI, and PPFD levels. In this article, we’ll dive into everything you need to know about these terms and how they relate to growing autoflowers.
What is PAR?
PAR stands for Photosynthetically Active Radiation, which is the spectrum of light that plants use for photosynthesis. This spectrum ranges from 400 to 700 nanometers, and includes blue and red light.
PAR is important to consider when growing autoflowers because it determines the amount of light that the plant can use for photosynthesis. If the PAR levels are too low, the plant will not be able to produce enough energy to grow properly, while too much PAR can lead to damage to the plant.
When it comes to autoflowers, it’s important to provide them with the right amount of PAR light for each stage of growth. During the vegetative stage, the plant requires more blue light, which helps with leaf and stem growth.
During the flowering stage, the plant requires more red light, which helps with the development of flowers and buds. Providing the plant with the right PAR levels for each stage of growth will ensure that it grows healthy and produces high-quality buds.
What is DLI?
DLI stands for Daily Light Integral, which is a measure of the amount of PAR light that a plant receives in a day. DLI takes into account both the intensity and duration of the light that the plant receives, and is measured in units of moles per day.
DLI is important to consider when growing autoflowers because it determines the total amount of energy that the plant receives in a day. For autoflowers, the ideal DLI levels vary depending on the stage of growth.
During the vegetative stage, the plant requires a DLI of around 10-20 mol/m2/day, while during the flowering stage, the plant requires a DLI of around 20-30 mol/m2/day. Providing the plant with the right DLI levels for each stage of growth will ensure that it receives enough energy to grow and produce high-quality buds.
What is PPFD?
PPFD stands for Photosynthetic Photon Flux Density, which is a measure of the amount of PAR light that falls on a given surface area per second. PPFD is measured in units of micromoles per square meter per second (µmol/m2/s), and is an important measure to consider when growing autoflowers because it determines the amount of PAR light that the plant receives at a specific point in time.
When it comes to autoflowers, the ideal PPFD levels vary depending on the stage of growth and the intensity of the light source. During the vegetative stage, the plant requires a PPFD of around 200-400 µmol/m2/s, while during the flowering stage, the plant requires a PPFD of around 600-800 µmol/m2/s. It’s important to note that providing too much PPFD can lead to heat stress, which can damage the plant.
How to measure PAR, DLI, and PPFD?
Now that we know what PAR, DLI, and PPFD are, the next question is how to measure them. There are several tools available to measure these metrics, including PAR meters, quantum sensors, and lux meters.
PAR meters are used to measure the amount of PAR light that a plant receives at a specific point in time. These meters typically have a sensor that measures the amount of PAR light and converts it into a measurement that can be read and analyzed. PAR meters are commonly used by professional growers and can be expensive, but they provide accurate and reliable measurements.
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Quantum sensors are similar to PAR meters, but they provide more detailed information about the amount of PAR light that a plant receives. Quantum sensors measure PPFD levels at a specific point in time, and can be used to calculate DLI levels over a period of time. Quantum sensors are a bit more expensive than PAR meters, but they provide more accurate and detailed measurements.
Lux meters are used to measure the intensity of light, but they do not provide information about the specific wavelengths of light that a plant receives. Lux meters are not recommended for measuring PAR, DLI, or PPFD levels for growing cannabis, as they do not provide accurate information about the spectrum of light that the plant needs for photosynthesis.
When measuring PAR, DLI, and PPFD levels, it’s important to take measurements at different points in the grow room or grow tent, as the light intensity can vary depending on the distance from the light source. Measuring at different points will help ensure that the plant is receiving enough light across the entire canopy.
How to adjust PAR, DLI, and PPFD levels?
Once you have measured the PAR, DLI, and PPFD levels in your grow room or grow tent, the next step is to adjust the levels to ensure that the plant is receiving the right amount of light. There are several ways to adjust the light levels, including changing the height of the light, adding more lights, or adjusting the light intensity.
Changing the height of the light is one of the easiest ways to adjust the light levels. Moving the light closer to the plant will increase the PPFD levels, while moving it farther away will decrease the PPFD levels. It’s important to be careful when adjusting the height of the light, as too much light can lead to heat stress and damage the plant.
Adding more lights is another way to increase the light levels in the grow room or grow tent. Adding more lights will increase the total PPFD levels, and can be especially useful during the flowering stage when the plant requires more light. However, adding more lights can also increase the heat levels in the grow room or grow tent, so it’s important to monitor the temperature and humidity levels.
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Adjusting the light intensity is another way to adjust the light levels. Most LED grow lights come with a dimmer switch that allows you to adjust the light intensity. Decreasing the light intensity will decrease the PPFD levels, while increasing the light intensity will increase the PPFD levels. It’s important to monitor the plant for signs of stress when adjusting the light intensity, as too much light can lead to heat stress and damage the plant.
Conclusion
In conclusion, PAR, DLI, and PPFD are important metrics to consider when growing autoflowers. Providing the plant with the right amount of light will ensure that it grows healthy and produces high-quality buds. Measuring and adjusting the light levels can be a bit tricky, but with the right tools and knowledge, it’s possible to create the ideal environment for your autoflowers to thrive. Whether you are a beginner or an experienced grower, understanding these metrics and how they relate to growing autoflowers is essential for a successful harvest.
