one of the beautiful things of indoor growing is that you can push your plants to the limits of yield, though experience and experimentations.
but, where is the actual limit?
in indoor growing (especially hydroponics) there is a limit of nutrients you can apply to your plant. depending on your strain, water hardness, lights intensities etc at a certain point you will do more harm then good by adding more and more nutrients (nutrient excess, or nute burn).
a similar point can be made for lights as well. we keep pushing the light intensity on the plants in order to have that 0.1-0.2 gpw increase, which in some cases makes it not even worth the effort.
but for light intensity there is a limit as well, which is the ability of the plant to absorb the light radiation through photosynthesis and CO2 fixation.
if we add too much light to our plants not only we don't gain any significant benefit, but we also force the plant to actually invest energy and resources towards dissipation of the excess light radiation. one main example would be the production of auxiliary pigments, like carotenoids, anthocyanins or xantophylls. this is quite visible when leaves in our plants start turning dark brown or even purple under certain light conditions.
ironically, one of the main factors which limits the plant photosynthetic capabilities is no others than one the most important photosynthetic enzymes: Ribulose-1,5-bisphosphate carboxylase/oxygenase (or more simply, RUBISCO). this particular enzyme catalyzes the fixation of CO2 into sugars (to oversimplify), and is a major bottleneck for the photosynthetically-derived enargy that plants can use to make sugars, starch, cellulose etc etc: ie the energy the plant can use to grow .
the problem of this enzyme is that also catalyzes a second reaction using oxygen (O2) as a substrate instead of CO2. both CO2 and O2 compete in the enzyme function: whoever is in the highest concentration inside the plant, the enzyme takes up and uses it for its reactions. this happens because this enzyme evolved millions of years ago, when the CO2 levels in the air where 2 to 5 times higher than they are now, making the problem of oxygen competition minimal.
when we apply too much light, the plant activates a protection mechanism called photorespiration. without many details, this process ends up increasing the O2 levels inside the leaf, further reducing RUBISCO efficiency towards photosynthesis and increasing the light dissipation pathways.
all this wall of text was for me to introduce the idea that, in order to push the limits of indoor growth even higher, we should consider using CO2 supplements in our growth chambers. increased CO2 levels have a drastic effect on increasing plant growth, as plants with more CO2 available grow faster. but more important, as i tried to explain above, it also allows to push the light limit even further, as plants are able to absorb and efficiently utilize more light.
have anyone tried higher CO2 concentrations in their growth chambers? (like 500ppm, 800ppm, or even 1200ppm). or even simples solutions like the CO2 bags or CO2 canisters?
let me know if you did and what results you got out of it
cheers
Dr Ghard
but, where is the actual limit?
in indoor growing (especially hydroponics) there is a limit of nutrients you can apply to your plant. depending on your strain, water hardness, lights intensities etc at a certain point you will do more harm then good by adding more and more nutrients (nutrient excess, or nute burn).
a similar point can be made for lights as well. we keep pushing the light intensity on the plants in order to have that 0.1-0.2 gpw increase, which in some cases makes it not even worth the effort.
but for light intensity there is a limit as well, which is the ability of the plant to absorb the light radiation through photosynthesis and CO2 fixation.
if we add too much light to our plants not only we don't gain any significant benefit, but we also force the plant to actually invest energy and resources towards dissipation of the excess light radiation. one main example would be the production of auxiliary pigments, like carotenoids, anthocyanins or xantophylls. this is quite visible when leaves in our plants start turning dark brown or even purple under certain light conditions.
ironically, one of the main factors which limits the plant photosynthetic capabilities is no others than one the most important photosynthetic enzymes: Ribulose-1,5-bisphosphate carboxylase/oxygenase (or more simply, RUBISCO). this particular enzyme catalyzes the fixation of CO2 into sugars (to oversimplify), and is a major bottleneck for the photosynthetically-derived enargy that plants can use to make sugars, starch, cellulose etc etc: ie the energy the plant can use to grow .
the problem of this enzyme is that also catalyzes a second reaction using oxygen (O2) as a substrate instead of CO2. both CO2 and O2 compete in the enzyme function: whoever is in the highest concentration inside the plant, the enzyme takes up and uses it for its reactions. this happens because this enzyme evolved millions of years ago, when the CO2 levels in the air where 2 to 5 times higher than they are now, making the problem of oxygen competition minimal.
when we apply too much light, the plant activates a protection mechanism called photorespiration. without many details, this process ends up increasing the O2 levels inside the leaf, further reducing RUBISCO efficiency towards photosynthesis and increasing the light dissipation pathways.
all this wall of text was for me to introduce the idea that, in order to push the limits of indoor growth even higher, we should consider using CO2 supplements in our growth chambers. increased CO2 levels have a drastic effect on increasing plant growth, as plants with more CO2 available grow faster. but more important, as i tried to explain above, it also allows to push the light limit even further, as plants are able to absorb and efficiently utilize more light.
have anyone tried higher CO2 concentrations in their growth chambers? (like 500ppm, 800ppm, or even 1200ppm). or even simples solutions like the CO2 bags or CO2 canisters?
let me know if you did and what results you got out of it
cheers
Dr Ghard