Light: Difference between revisions

25 bytes removed ,  10 September 2023
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(→‎Ideal light conditions: Correction on low light for seedlings)
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The threshold for optimal growth and photosynthesis, from the vegetative stage, is a DLI of 65 moles.<ref> Daily Light Integral DLI Relation To Cannabis Yield (Meta-analysis, Matthew Debacco, 2021) https://www.youtube.com/watch?v=au7G-oVDeKg</ref>
 
Yield appears to be linear with PPFD to around 2000 μmol/s<ref>Cannabis Yield, Potency, and Leaf Photosynthesis Respond Differently to Increasing Light Levels in an Indoor Environment (Rodriguez-Morrison, 2021) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8144505/</ref><ref>High Light Intensities Can Be Used to Grow Healthy and Robust Cannabis Plants During the Vegetative Stage of Indoor Production (Moher, 2021) https://www.preprints.org/manuscript/202104.0417/v1</ref>. Above 500 μmol/s supplemental co<sub>2</sub> is advised to make optimum use of the light.<ref>Fluence Cannabis Cultivation Guide, 2020 - https://fluence.science/guides/cannabis-cultivation-guide/</ref>
<ref>High Light Intensities Can Be Used to Grow Healthy and Robust Cannabis Plants During the Vegetative Stage of Indoor Production (Moher, 2021) https://www.preprints.org/manuscript/202104.0417/v1</ref>
 
Temperature and light optima for photosynthesis were concluded to be at 25–30 °C and ∼1500 μmol m<sup>2</sup>/s respectively<ref> Photosynthetic response of Cannabis sativa L. to variations in photosynthetic photon flux densities, temperature and CO2 conditions (Chandra, 2008) https://dx.doi.org/10.1007%2Fs12298-008-0027-x</ref>
The theoretical upper limit that a plant can tolerate before experiencing symptoms of poor health.
 
The Maximum PPFD cannabis can tolerate is around 2000 - 2500 μmol/s in perfect conditions<ref> Light dependence of photosynthesis and water vapor exchange... (Chandra, 2015)- https://doi.org/10.1016/j.jarmap.2015.03.002</ref><ref> Cannabis business times Oct, 2021 https://www.cannabisbusinesstimes.com/article/growing-under-high-light-intensities-lighting-report/</ref> and a DLI of around 40 - 60 moles. Above 500 μmol/s supplemental co<sub>2</sub> is required,<ref>Fluence Cannabis Cultivation Guide, 2020 - https://fluence.science/guides/cannabis-cultivation-guide/</ref> without it more intense light level will harm the plant.
 
Meta-analysis of plant morphology to light intensity.<ref>A meta-analysis of plant responses to light intensity for 70 traits ranging from molecules to whole plant performance (Poorter, 2019) https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.15754</ref>