LED Grow Lights for Cannabis: Understanding PAR and PPFD

There are two key metrics to understand when it comes to LED grow lights, which have recently become a favorite with growers. These are PAR and PPFD.

PAR stands for Photosynthetically Active Radiation, which refers to the spectrum of light that plants use for photosynthesis, specifically wavelengths between 400-700nm. PPFD stands for Photosynthetic Photon Flux Density, which refers to the amount of PAR falling in a given area per second.

PPFD is measured in micromoles per square meter per second (μmol/m2/s) and is a more accurate way of measuring light intensity for plant growth than traditional measurements such as lux or foot candles. PPFD takes into account both the intensity and quality of light, which are important factors for plant growth and yield.

LED Grow Lights for Cannabis: The Importance of PAR and PPFD

When choosing LED grow lights for marijuana, it is important to consider both PAR and PPFD. Look for lights with a high PAR output in the 400-700nm range, as well as a high PPFD output at the canopy level of your facilities. Different stages of plant growth require different PPFD levels, so it's also important to consider the recommended PPFD levels for each stage of growth when choosing LED grow lights.

There are some additional points to consider when it comes to PAR and PPFD in LED grow lights for cannabis, so let's take a quick look at them:

Spectral Distribution:

While PAR is important, it is also important to consider the spectral distribution of light. Plants use different wavelengths of light for different purposes, such as blue light for vegetative growth and red light for flowering. Look for LED grow lights that provide a full spectrum of light, including the wavelengths that plants need at each stage of growth.

Distance from Plants:

PPFD levels can vary depending on the distance between the light source and the plants. As a general rule, the closer the light source is to the plants, the higher the PPFD. However, it is important to balance high PPFD levels with the risk of mild burns or heat damage to plants.

Light Schedule:

Cannabis plants require different amounts of light at different stages of growth. In general, plants need more light during the vegetative stage and less during the flowering stage. It is important to choose LED grow lights that can be customized to the specific light scheme required for your plants.

Heat Output:

LED grow lights can generate heat which can affect the temperature and humidity levels in your grow area. Look for LED grow lights with efficient cooling systems or low heat output to minimize the impact on your growing environment.



As cannabis growers, you must consider many factors to choose the right wattage for LED grow lights. We have listed important information for you to help you choose the right wattage for your cannabis grow lights.


The Ultimate Guide to Choosing Wattage for LED Grow Lights for Cannabis


Determine the size of your growing area:

The wattage you need will depend on the size of your growing area. A small growing area of 1-2 plants may require approximately 150-250 watts, while a larger growing area of 4-6 plants may require 400-600 watts.


Consider the growth stage:

The cannabis plant has different light requirements at different stages of growth. Plants need more blue light during the vegetative period and more red light during the flowering period. Make sure the LED grow light you choose provides both types of light.


Look for high quality LED chips:

The quality of the LED chips used in the grow light will affect the intensity and extent of the light. Look for LED grow lights that use high quality chips like Cree or Bridgelux.


Check the PAR value:

The PAR (Photosynthetically Active Radiation) value of the LED grow light will give you an idea of its intensity and effectiveness. Higher PAR values mean more intense light, which is important for achieving higher efficiency.


Consider the cooling system:

LED grow lights can generate a lot of heat that can harm your plants if not managed properly. Look for LED grow lights with good cooling systems like heat sinks or fans.


Check out the full spectrum LED grow lights:

Full spectrum LED grow lights provide a wider range of light wavelengths that can be beneficial for plant growth and development. They are also more energy efficient and can save you money on electricity costs.


Consider the type of cannabis strain:

Different cannabis strains have different light requirements. For example, Sativa strains may need more light than Indica strains. Research the specific light requirements of your chosen species to help determine the right power for your LED grow lights.


Calculate the total power required:

If you plan to use multiple LED grow lights, be sure to calculate the total power required to cover your grow area. It is better to have slightly more wattage than is required to provide adequate coverage and light intensity.


Look for adjustable wattage options:

Some LED grow lights come with adjustable wattage options that allow you to increase or decrease the intensity of the light as needed. This can be useful for controlling the growth and development of your plants.


Consider the lifetime and warranty:

LED grow lights can be a significant investment, so make sure you choose a high quality product that is long lasting and guaranteed. Look for LED grow lights with a lifespan of at least 50,000 hours and a 2-3 year warranty.



No Products in the Cart