Help! Anyone know what the problem is

S

Stoneisland3529

Member
Bottom leaves going brown on the tips - unsure what the issue is.

I am growing in coco, feeding until run off daily. My PH is 6.0 and I am using a HPS bulb on 250watts. The distance of the light is 30 inches away. My temps stay between 22 - 25 degrees and my humidity is between 50 - 60%
 

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DeadHeadX

DeadHeadX

Well-Known Member
Is the light on full blast? If so, the seedling doesn’t need that much yet. Could be too much, too powerful light
 
Fish scale

Fish scale

Well-Known Member
DeadHeadX said:
Uhm, I think this is incorrect. PPFD is simply a different light measurement, but everything from the sun to a lightbulb can be measured with this unit.
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I never knew that, I always thought HPS light was measured in lumens and LED was measured in PPFD?
 
DeadHeadX

DeadHeadX

Well-Known Member
Fish scale said:
I never knew that, I always thought HPS light was measured in lumens and LED was measured in PPFD?
Click to expand...
My understanding is that they are different measurements. Lumens measures the light emitted from a bulb. PPFD measures the photons received by the plant. Neither is limited to any particular light source. Of course, my knowledge is pretty rudimentary. Others might come to correct me or add detail. But ppfd is definitely a universal measurement.
 
G

Grower1974

Member
PPFD is actual active light photons.
Lumens is what’s perceived by humans, but can be used on plants. With lumens, there can be more or less photons at the same lumen measurement based on the type of light used/spectrum etc. So it can be very vague.
 
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