Distribution Of Sugars Within A Marijuana Plant

To grow some high quality marijuana, the plant needs to make a lot of sugars. The full grown leaves produce these sugars for the buds and young leaves so they can grow.
It’s very important that these sugars go to the right place, but how are sugars produced and can you increase the production by trimming away leaves?

In general I advise to keep leaves in place till the plant discards them of by itself. I’m talking of course about the large fan leaves. Trimming young leaves and young side shoots can however lead to better distribution of sugars (=higher yield), but only if your plant retains its larger fully grown fan leaves.

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    The production of sugars

    The production of sugars in cannabis

    A plant catches sun rays on its leaves and converts this energy along with CO2 and water into sugars. This process is called photosynthesis. The evaporation gives the plant the chance to take up water and nutrients through its root system and transport them throughout the plant.

    Sugars in particular are very important building blocks for the plant. The sugars are carefully divided to specific parts of the plant.

    The actual yield depends mostly on the amount of sugars the large fan leaves can produce and the amount of sugars that are eventually transported to the buds. You can roughly say that two thirds of the sugars go to the buds, which is a lot. Young foliage that’s still developing also requires these sugars.

    Noticeable is that every plant has a fixed ratio when it comes to dividing the sugars. These ratios, sadly, are hardly influenced by nutrients, temperature, light or CO2.

    We are only interested in the buds, so it would be nice to be able to influence the distribution a little bit.

    Distribution of sugars

    Distribution of sugars within a cannabis plant

    The principal behind the distribution of sugars is the so called sink strength. All the plants organs function like individual sinks which the sugars flow towards. However the suction of the sinks are not equal in strength. The buds have the most suction, especially when they are half way in their development.

    Young, new foliage also needs a  lot of sugars while matured leaves create more sugars than it needs. These old mature leaves provide the buds and young foliage with sugars and for that reason they are very important.

    Within the plant there is a lot of competition for the sugars. All parts of the plant are pulling on the available sugars. Pulling harder means more sugars. So organs with larger sink strength always get more than the ones with lower sink strength. Example: a main bud with sink strength of 3 will get 3 times as much sugar than a leaf with sink strength of 1. These ratio’s always stay the same, whether there are a lot of sugars or hardly any available.

    Better distribution by trimming

    Better distribution by trimming

    With the above mentioned principals in mind we can now start to trim the plant for a better distribution of the sugars.

    By removing young foliage before they start to use up energy, more sugars will automatically go to the buds. Pay close attention when removing. Make sure the plant keeps enough foliage and fan leaves to make sugars. The foliage needs to be dense enough so no light can pass through to the pots, so we don’t waist energy.

    Personally I would not trim fan leaves. The top fan leaves catch the most light and automatically have more chloroplasts, so they can produce more sugars. But the bottom foliage also catches a little light and contributes to the sugar production. Why remove a fan leave when the sugar production is higher if you leave it be.

    In the event that a fan leave is that much overshadowed by the top leaves and it’s actually using up more sugars than it is producing (becoming a sink, once again). The plant will then sacrifice suck dry and disregard this leave and it will fall off by itself. The plant has its own solution for such matters so why not just leave it to the plant.

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    Robert Bergman

    Robert Bergman is an Amsterdam-based marijuana grow expert who has years of experience from small grows to massive operations. His passion for growing lead him to develop his own Gold Leaf strain. Now, Robert is dedicated to sharing his knowledge with the world.... [Read full bio]


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      13 comments on “Distribution Of Sugars Within A Marijuana Plant”

      1. Tony,

        Removing fan leaves is not a viable way to make bigger buds because you are robbing the plant of sugar producing leaves if you do.

        More light usually means more buds. Causing stress to the plant by removing fan leaves will hurt more than it helps.

        Did you watch the video in this article?
        Happy growing 🙂

      2. what’s the best way to make the biggest buds and trim the shade leaves and I have decent buds and I have good size cola buds going any ideas of the best way to make them grow bigger before harvest time next month

      3. […] use light to combine the elements in water and carbon dioxide to produce sugar and release oxygen. Sugar is the primary building block for tissue growth—including bud […]

      4. You can do this. It will probably slow down the other buds that have been left on the plant but they will continue to mature. I would also try to cover the stems that you have cut to minimise water loss (with gaffer tape or melted beeswax or something similar).

      5. Great article! I just finished my 1st grow indoor and was satisfied with it! learning a lot!

      6. Hi Robert ,,, regarding trimming ,, I tend to remove all the small growth from the bottom when plant flower. One question I do have however and it may seem stupid to some or prob most ,,,,when harvesting sometimes you see that the top of the plant is ready but some of the bud farther down could do with another week or so ,,,,,with that in mind
        Would the shock caused by cutting the top off be such that it would not allow further ripening of the bottom buds ??

      7. Blunt: the article is about blooming plants – not babies. You are doing something wrong if more than about 1 leaf a day drops from a non flowering plant.

      8. Robert, should new leaves developing around the base of freshly formed buds be trimmed off to encourage greater sugar distribution to the bud? What about smaller leaves growing at the branch nodes near the stem? I want everything to go to the buds, but don’t want to shock the plant in the process. Thanks, John.

      9. Good article and in particular about the sink strength and sugar distribution. I have seen a growers plants be stunted and held back as a result of removing too many of the mature dark green fan leaves, it affected the plant so much the harvest was about 1/3 of normal. If the plants leaves are receiving light then they are helping the plant by producing sugars. Always think twice before removing leaves that are mature ( not old ) and receiving light.

      10. Great food for thought. I’m a new grower learning alot every day.
        I thought that growing indoors it is important to thin out dense growth to allow ventilation to the plant and to help prevent mold etc… Please correct me if this is wrong…. and thanks again Robert for such a great site, products, articles on growing…all very helpful…Especially that very excellent seeds that I’ve received. Thanks!