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Effects of Light Intensity on Plant Growth

puggle6

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From my observations also have to say the strain/genetics are playing the most part for overall result.

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Hey everyone, been AWOL for a few months, had some "real life" things to contend with. Hoping to slowly work my way back into the AFN crowd once again. Hope all's well with you all. Updates coming soon.
I just was wondering about you. Good to have you sitting on our back porch again. Check out my latest grow when I have posted all the weights.
 

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So, did we come to any conclusions? Any ideal numbers to share?
 

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  • Blue (400 to 500) light inhibits stretch
  • Red (600 to 700) encourages stretch
  • Far red (700 to 800) can be used for photosyntesis too, provided you have enough in the 400 to 700 range.

An increase of 10% blue light can drastically decrease the internodal distance a plant, which can be useful if you wish to grow in a small space. You can vary the spectral intensities you supply to your plants over the course of it's lifetime to control how it grows example:
Week 1: Red heavy to get the primary nodes off the ground
top the apex
Week 2-4: Still red heavy to get a wider footprint
flower start
Week 5 to 6: Blue heavy to keep the initial stretch down and minimize the popcorn delta
Week 7+: Balanced to let the final stretch and apical bud formation happen naturally.
after all, big buds look nice and are preferable to budsicle stones

Now we know light is subject to an inverse square falloff, and since red has less energy than blue it doesn't make it as far at the same intensity. So moving your light farther away will make plants stretch more. Marginally more than dimming a closer light to reach the same DLI (assuming a 400 to 700 par spectrum).
 
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