I have had this question throughout the time that I have been gardening. Where exactly does the carbon that goes into the plant structure? Is it like the nitrogen cycle? Does it come from the air? Is it from the ground? Is it a combination? I recently saw a presentation on soil where the roots go between the soil particles. Does it get some carbon there?

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    This question appears to be off-topic because it is about biology?
    – Patrick B.
    Mar 27, 2014 at 22:26
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    @PatrickB. understanding why something happens can help one do facilitate it. Jmusser may learn the biological process so that he may supply his plants with adequate carbon, and in the correct way.
    – JoJo
    May 19, 2014 at 15:18
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    It was freddydoggie who asked the question. I do not doubt the usage of learning things. I was just suggesting that another site might give an even better answer.
    – Patrick B.
    May 19, 2014 at 15:23
  • CO2 in the atmosphere combined with hydrogen. Through photosynthesis, sugars and complex carbohydrates are generated to both feed and create plant structure. May 19, 2014 at 16:31
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    This question appears to be off-topic because it is about biology, not gardening/landscaping as defined in the help center.
    – J. Musser
    Jun 20, 2014 at 2:51

1 Answer 1


Generally, carbon dioxide enters a plant through stomata on the leaves - these are like small pores on the underside of the leaf with two guard cells which allow CO2 to enter, and oxygen to leave. Part of the photosynthetic process, and there's a formula for it - six molecules of C02 plus six molecules of water turns into 1 molecule of sugar (which the plant utilises) and 6 molecules of oxygen (which it emits from the stomata). The water comes from root uptake in the soil, but some water loss is inevitable through the stomata too.

Plants without proper leaves have stomata placed elsewhere (stems, for instance).


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