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PAR/PPFD and light height
GreenHillZonestarted grow question 4 years ago
PAR/PPFD: does light height matter if your PPFD is in the right range? Another way to ask: is 300 PPFD @ 2 feet the same as 300 PPFD @ 20 feet, or are there other factors involved? (assuming heat, C02, all other non light inputs equal)
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The8thChevronanswered grow question 4 years ago
For the most part, these things are equal whether they are 2 inches or 2 feet. You want to go by ppfd.
Things that DO change with height? Penetration will decrease as the light is moved further away. Coverage area will decrease as the light is moved closer. Generally, I try to keep my light at maximum power and have the correct PAR.
Ppfd:
Seedlings 400
Veg 600
Bloom 900
You can increase ppfd if you use CO2.
GrowCNanswered grow question 4 years ago
I set my light height and power based on PPFD. When plants are young and smaller I will lower the light and adjust the power to match what the plant needs. Then when flowering and I want light bouncing off the walls of the tent for the side and bottom leaves I raise the light to a high position and crank up the power. I also get more even lighting throughout my tent when the light is higher with the power turned up.
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