Hello Forum,
I have a question about light power:
Is it better to always keep the light at 100% and to raise the light, or put a light at 50%-75% and later at 100%?
Thank you 
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I think its better to dim if ur able to
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I like my lights close to the canopy for better penetration. If that means lowering light intensity then I do that.
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What stage of the grow?
The LightMan once suggested 100% power is better then dimming.
Once in veg I run 100% power and adjust height as needed.
This will be a Chevy-Ford type of subject 
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Does it mean that, as long as the plants receive the right amount of ppfd, lights can be dimmed even lower?
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Almost ready to be flipped, stage.
Is Chevvy-Ford a Forum participant?
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Then a quick search found this…
Dimmable LED Spectrum Shift
Based on the search results, here’s a summary of the findings:
According to Horticulture Lighting Group, dimming full-spectrum white LED grow lights has a very small impact on the spectrum, and this impact can be ignored for horticulture applications. (Source: “Does Dimming LED Change Spectrum”)
Another source suggests that dimming an LED grow light has little or no effect on the output spectrum. (Source: “What happens when you dim your grow lights?”)
In general, LED grow lights are designed to emit a specific spectrum, and dimming them does not alter the underlying spectral composition. Instead, it simply reduces the overall intensity of the light.
Some sources emphasize that LED grow lights are engineered to maintain their spectral characteristics even when dimmed, as they do not suffer from the same heat-related spectral shifts that can occur with HID bulbs. (Source: “Should I Dim My LED Grow Lights?”)
In terms of specific LED grow light designs, some models may offer adjustable color ratios or spectral distributions, allowing growers to tailor the light to specific growth stages or plant types. However, this is a design feature rather than a result of dimming.
In summary, dimmable LED grow lights do not lose their spectrum when dimmed. The spectral composition remains consistent, and the dimming function only adjusts the overall intensity of the light. This is a key advantage of LED grow lights over other types of grow lights, which can experience spectral shifts when operated at reduced power.
@dbrn32 what’s you take
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Sorry I forget your local 
Let’s call it a Ferrari - Maserati 
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OK!! I got it now!!
Which one is better…
Thank you for the articles, sometimes I can’t phrase the search in the right way and online search gets frustrating.
PS: A Ferrari
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Ok, that makes sense.
To consider as well is that by raising the light then the plants could stretch, also, if they made the lights dimmable, there must be a reason
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Raising and lowering lights won’t change your light output or theoretical ppfd average. Dimming your light will. So it really depends on what you’re trying to accomplish.
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I dont like to raise or lower my lighting. It is fixed at the top of my tent. I like to run my power at about 75% and keep my canopy at about 16" so since I do not move my light I use boosters all through my grow to keep the canopy at 16" and then only use the dimmer to dial in my DLI based on stage she is in.
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Ok, but, if my plants get ppfd 700 at 100% light or ppfd at 700 lowered down and at 75%. light, why is it one better or worse than the other?
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“In summary, dimmable LED grow lights do not lose their spectrum when dimmed. The spectral composition remains consistent, and the dimming function only adjusts the overall intensity of the light. This is a key advantage of LED grow lights over other types of grow lights, which can experience spectral shifts when operated at reduced power.”
The summary of an article @StonedCold13 published explains that if the light output is less the spectrum is the same. Sounds good to me 
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Not to mention it could be a pain to lower and raise the lights, especially alone
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This is an issue with the way you are measuring light. Moving the light lower doesn’t put out more light it just condenses the throw of light. Where it’s going up in the middle there is an adverse reaction on the edges. Unless your light was just too high to start with and bouncing too many photons off the wall before they made it to canopy. The walls don’t reflect 100% of light and will have heat losses if your light is too high. If you check definition of ppfd its equal to ppf/area. Moving light doesn’t change ppf of light.
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The only reason I can think of to run lights at a higher setting than is necessary to meet your DLI target in 18 or 12 hours is to warm the tent. 
I don’t know how the electrical efficiency of this method compares with a purpose-built heater, but it’s easy.
Really? Aren’t you using adjustable hangers like these:
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Absolutely! 1000 watt heater putting out zero effective light is 0% efficient as a grow light. Running a little more light than is needed will drop efficiency but it will still be significantly better than 0.
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Hello, dear @Venturi.
For the big tent I use the one in the picture, which is good, but the light is the bigger one and, particularly alone, it’s hard.
In the smallest tent, I use the one in your picture, which came with the light
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But…if i move the light higher, or lower, the ppfd does change,
I am confused 
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