Chlorophyll in Cannabis

The foundation of plant growth is photosynthesis. In this process, plants harness the energy of sunlight to turn carbon dioxide into the various materials needed for plant growth. Photosynthesis itself is made possible because of specialized proteins embedded with chlorophyll, which are in turn contained within photosynthetic cell membranes known as chloroplasts.

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Chlorophyll primarily absorbs red and blue light and reflects away wavelengths of green light. This is one reason that plant foliage is usually so green throughout the year. Other colors in leaves don’t because visible until after maturity when the chlorophyll in the foliage begins to decay and reveal other colors.

Chlorophyll is split into two slightly different types: chlorophyll a and chlorophyll b. The primary differences between these two types of chlorophyll are the frequency of light they absorb and their general chemical composition. Chlorophyll a absorbs red and violet sections of the spectrum, ranging from 430 to 662 nanometers while type b absorbs a wider range between 400-700. This latter spectrum is known as PAR (Photosynthetically Available Radiation). PAR can be measured by the number of light particles that strike a square meter every second. This allows growers to assign a PPFD (Photosynthetic Photon Flux Density) index number to a plant and determine how much usable light that the plant is being exposed to.

LED – Light emitting diodes


LEDs (light-emitting diodes) have become ubiquitous in the lighting world over the last decade. While not necessarily the ideal light for growing cannabis, LED lights offer several advantages.

First of all, they are low voltage, which means less money spent on upkeep and electricity to keep them running. Coupled with this, they produce very little heat, which means you don’t need to worry about overheating your grow room if you use LED lights. It also further reduces your reliance on ventilation and fans, adding even deeper energy savings. In fact, depending on your operation, you may very well need to heat the room if you are using LED lighting.

For growers prioritizing privacy, LED lights offer an additional bonus— the low heat makes LED lighting virtually impossible to detect with thermal imaging techniques commonly used to spot the infrared heat of more conventional HPS lights. LED lighting is also quieter than the other lighting options, without the background hum emitted by HPS lights.

Remember that not all LED lights are created equal! Be sure to check your bulbs and make sure that they are high-wattage and have a high lumen value. The higher these are, the brighter your light will be. You also want to make sure that LED lights you choose have been specifically manufactured to emit light at the full spectrum of color your plants need for proper photosynthesis.

LED lights do have a higher initial investment than some of the cheaper options, which can cause some growers to be skeptical about using them. Then again, they are very efficient. LED lights waste far less energy as heat, assuming the room doesn’t need to be heated, and those savings on electricity will pay for themselves in just a couple years. You also don’t need to worry about setting your grow room on fire, and LED lights last for a long time. Some manufacturers advertise more than 100,000 hours of life in their LED bulbs, which gives you enough time for almost ten years of harvesting. Click here for the best LED lights for marijuana plants

CFL – Compact fluorescents


Besides LED and the more traditional HPS lighting available, growers can use fluorescent fixtures. These used to be commonly used by farmers for germination and indoor growing. They’re easy on the wallet, which makes them an excellent choice for any growers operating on a tight budget, or hobbyist growers that don’t want to invest too much right off the bat. Fixtures come in both long tubes and also spiral bulbs that fit into conventional sockets. Either works, depending on what is most convenient.

Fluorescents won’t be as bright as incandescents or LED lights, but they can produce adequate light, and run much cooler than incandescents. That means you can place them closer to the plants without worrying about burning or damaging the foliage. Sometimes growers will use fluorescent lights in conjunction with more powerful lamps to increase the light in their grow room without increasing heat.

As with the LED lights mentioned above, compact fluorescent lights use significantly less electricity than incandescents. They also emit far lower levels of heat, which is good for both privacy and the health of the plants themselves.



Efficiency is the name of the game when it comes to lighting your grow room. As a grower, you want to use all of the light that you’re producing, and that means you need reflectors. Some growers favor using mirrored surfaces. You can pick up cheap floor mirrors at any major department store and stand them against the interior walls of your grow room. The major downside to using mirrors is that you need to clean them regularly in order to keep the effective. Just be careful to clean them with something that won’t damage the integrity of your plants.

An even cheaper alternative to using mirrors is to purchase aluminum foil. Just line all of the interior surfaces with the foil and tape or staple it down as needed. Make sure you have the shiny side facing up! As with mirrors, the foil can become dirty and lose its reflective properties, but it’s easy to replace when necessary. Foil can also be laid under the plant, helping reflect even more light back up at the leaves and preventing water from evaporating out of the soil. More about reflective material

Lastly, you can use potato chip bags! Believe it or not, the reflective interior of these bags work very well at reflecting light, and obviously they are very very cheap. Just be careful— too much heat can easily cause these bags to melt or ignite, especially if they are all greasy.

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Finally, remember that the genetics of your plant will play a huge role in the end result. You just won’t get the highest quality buds from poor genetics, even if you are optimizing the environment and getting your plants all the light they need.

Thanks for reading. Please leave comments or questions below and don’t forget to download my free grow bible


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Mr Robert Bergman PhD


Robert Bergman is an Amsterdam-based marijuana grow expert who has years of experience from small grows to massive operations ... See profile

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8 comments on “Chlorophyll in Cannabis”

  1. I’ve been wondering if I could use a black light at night when I bring my plants in. I live where they should not be left outside. any thoughts on that would be helpful.

  2. Yes, I too would like to know, what is the best distance from plants for LEDs in the vegetative period and the flowering period?