- The Weed Blog https://www.theweedblog.com

How Does A Marijuana Plant Convert Light Into Energy?


marijuana washington state felony drug possessionA marijuana  plant needs energy, just like humans and animals. The plant takes the energy through the leaves (chlorophyll), from the light. This is known as photosynthesis. Along with carbon dioxide (CO2) from the air and water (H2O) from the soil, the light is converted into energy.

But not all light is suitable. The light needs to have a specific wavelength (color) and intensity (strength) in order to make the photosynthesis occur properly. It even requires more precision. Depending upon the processes occurring in the marijuana plant, the plant needs a certain light. Blue light, in particular, is needed for the growth process, while the bloom process requires orange and red light. This is the reason why not every lamp is sufficient and you need to use a special grow and bloom lamp.

Exposing the marijuana plant to light sets the following chemical reaction in motion;

Light energy + carbon dioxide + water <—> sugars + oxygen

The arrow in the center indicates that the reaction can go two ways. The arrow to the right means that during the daylight period the CO2 and water are converted into sugars. The marijuana plant gets the energy needed for this, via the chlorophyll from the leaves, from the light. The oxygen that remains is a waste product for the plant and is excreted through the leaves. This is called the carbon dioxide assimilation process. This article is part of the e-Book ” The Marijuana Grow Bible”. Make sure to download it for free at this link here.

The longer the energy is available, the longer the factory can run and the marijuana plant can grow or flower. The stock of nutrients in the water is limitless, and you are in complete control of the length of the daylight period. It seems obvious to keep the night as short as possible, preferably to skip it altogether, but it’s not that simple.

At night other necessary processes take place, such as the production of proteins. The energy needed for this involves the same chemical reaction, but then from right to left. The sugar stored energy and oxygen is converted into water vapor and CO2. This is known as dissimilation, or the breathing of the plant. The plant uses this energy to make other proteins which are not formed with the assimilation during the day. For this reason a marijuana plant requires a day and a night period.

Research shows that a daylight period of 18 hours is the maximum and best during the growth period. In fact, it’s an imitation of the longest day in summer, when the marijuana plant experiences its most important growth period.

During flowering, the daylight period may not be longer than 12 hours. In this case the fall season is imitated, when the plant goes through its most important flowering period. Giving it light for longer than 12 hours may result in the plant going back into growth. So you have to make sure that your marijuana plant has enough available light, and that it’s of the right color and at the right moment.

Want to start growing marijuana? All top quality marijuana seeds are available in my marijuana seed shop. We ship seeds to the US, CA and many other countries. For any growing related question please visit the marijuana support page.

Source: ILoveGrowingMarijuana.Com



About Author

Robert Bergman is a master marijuana grower. Robert Bergman is the author of 'Marijuana Plant Care' and 'The Marijuana Grow Bible'.


  1. You did stumble into a good point though, the Law of Conservation of Energy. The plant is indeed converting the light energy into stored energy in the sugars. Some very small amount of energy is lost along the way, as heat or otherwise, since nothing can be 100% perfectly efficient. I don’t know the exact number, it probably varies alot, but if I had to guess, I would say that plant photosynthesis is probably about 85% or 90% efficient. If we could build an engine that was 85 or 90 percent efficient, it would probably get about 1000 miles per gallon lol! An engine looses much of its energy to heat directly, and then looses much more with friction of every single moving part! The Law says energy and mass cannot be created or destroyed, it just changes forms :) The plant does gain mass as it grows, but very simply, it’s just rearranging molecules that already exist, along with light energy to sugars, to build itself into a plant. Some food for thought :)

  2. I wrongly assumed that light energy is converted to mass in photosynthesis. My assumptions are quiet obviously wrong after reading up on photosynthesis. And logically, if light were converted to mass, the mass of the whole earth would increase, and that makes my assumptions silly, to say the least.

    And this got me thinking about how it feels to be wrong? A very important question in the legalization debate.
    How do you ask someone to consider they are wrong about marijuana prohibition?

  3. I may have to dust off my physics books, but I think light energy is converted into mass through the process of photosynthesis. Something about Maxwell’s conservation of energy laws. Oh well, who cares, we all know what he’s talking about.

Leave A Reply