CobKits
Well-Known Member
i tend to agree with greengenes as i run in a tent, but it also depends on situation. if they are tiny clones, dimming is fine. if they are really tall you will lose out on a lot of "penetration" (i hate that term as its so abused) by running too close
like as an example say you can get 700 ppfd to the top of canopy by either dimming or raising the lights and running it hotter:
dimming at say 6" distance: 700 ppfd at canopy, your light intensity will rapidly fall off 6-12" into the canopy as that is 2 and 3x the distance from light to top of canopy
raise light to 18" and crank it up: same 700 ppfd at the canopy, and much higher ppfd at 6 and 12" below canopy than the example above, as it is now only 1.33x and 1.66x the distance from light source to top of canopy at those respective depths. You can use the inverse square "rule" (which isnt super applicable in many applications but should give you at least a minimum intensity by pretending youre in an open non-reflective space
PLUS if in a tent or appropriately sized room youre getting all the reflected light off the walls penetrating lower canopy from different angles
like as an example say you can get 700 ppfd to the top of canopy by either dimming or raising the lights and running it hotter:
dimming at say 6" distance: 700 ppfd at canopy, your light intensity will rapidly fall off 6-12" into the canopy as that is 2 and 3x the distance from light to top of canopy
raise light to 18" and crank it up: same 700 ppfd at the canopy, and much higher ppfd at 6 and 12" below canopy than the example above, as it is now only 1.33x and 1.66x the distance from light source to top of canopy at those respective depths. You can use the inverse square "rule" (which isnt super applicable in many applications but should give you at least a minimum intensity by pretending youre in an open non-reflective space
PLUS if in a tent or appropriately sized room youre getting all the reflected light off the walls penetrating lower canopy from different angles