Do roots REALLY grow in the dark?

Discussion in 'Marijuana Grow Guide' started by Steve Cool, May 13, 2011.

  1. Steve Cool

    Steve Cool Tokemaster General Staff Member


    Many times you see in posts that “roots grow during the dark.” If this were true, the 24/0 photoperiod would result in a plant with a tiny root structure, if one at all! We know this is not the case. So... how does it actually work?

    To simplify things, lets use an analogy. Try to think of a plant as a building… one constantly under construction. The plant needs raw materials (fertilizers and water) and energy (light) in order to build itself. The raw materials are the bricks and mortar of the building and the energy is the workers and tools used to assemble the building.

    The plant is capable of storing some raw materials and some energy for use later, but the amount is limited...think of a warehouse and a battery, respectively.

    During the day (lights ON) the plant is collecting and storing light energy and is using and storing raw materials as it is building itself.

    At night (lights OFF) there is no light energy so the plant must rely on energy it stored while the lights were ON. Essentially, the plant is running on batteries and using raw material from the warehouse. Since the plant needs energy to absorb more raw materials, it is easier for the plant to use raw materials that it stored during the day than it is to absorb new raw materials through its roots. In other words, it does the plant no good to waste it's battery refilling the warehouse.

    Although the plant is capable of “doing it all” with the lights on (collect, store, and use energy and raw materials), this is not very efficient and it does a better job of actually doing the work while the lights are out.

    One last thing to remember is the fact that a plant will always strive to maintain a balance between the size of its roots and the size of its canopy (leaf mass). The roots must be big enough to supply as much raw materials as the canopy can use, and the canopy must be big enough to provide the energy required to uptake and store those raw materials.

    • Trim the roots on a healthy plant, and canopy growth will slow to a crawl until the roots have grown big enough to again support the canopy.
    • Trim the TOP of a healthy plant, and root growth will slow similarly, until the canopy has grown big enough to again support the roots.
    • If the plant is already in balance, the canopy and the roots will grow at the same rate.

    If you actually measured them several times daily over several days, you’d notice that they actually DO get bigger at night (roots and canopy at the same rate, unless either has been trimmed) and as long as the “batteries” hold out.
  2. n0va59

    n0va59 New Member

    Holy cow you can explain things well....I am sooooo glad I decided to click on this thread

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