Dimmable LED Question

[Jin Terra]

Greetings!

I have a question on dimmable LED lights. I purchased a 450 light. It has three dimmable controls (red, blue & white). I'm curious to know if anyone has experience with dimmable lights and some examples of settings they use throughout their grow.

I've grow before but it's always been with HPS/MH. This grow I'm looking to do will be in DWC with organic nutes.

The manufacturer recommends the following: (18/6 Veg & 12/12 Flower)

First 3-5 days: 50% for Blue and White
Seedlings: 80% Blue and White and 30% Red at 28"-32" away.
One to Two weeks in: 100% for Blue and White and 50% Red at 22"-28" for rest of veg.
Flowering: 100% for all three at 16"-22"

While I can see where the manufacturer is coming from with these recommendations, I think ultimately it will go by the strain and what it demands. Does anyone have a blanket setting for this kind of light they use or do you go by strain and setup?

 

[greensunshine]

Hey this is a great question. Blue light has been shown by science to reduce plant size especially in veg so if you want explosive results try starting with red 100%, white 100% and blue only on a little bit, and turn on blue as plants go into flower to get those extra photons.

In my experience with dimmable LEDs it's best to have it using at least 50% power at all times and hung very high above your plants or else it will take a long long time for your plants to get used to the extra light. To your plant when the light is hung high it is a strong intensity but has less light coming from one angle which can burn your plants, it comes from all angles so your plant gets used to the "high" amount of light but doesn't get burned.

 

[Leafy Greens]

If you look at the curve for light spectrum based on what the plants need, there is a higher peek at red than blue. The proposed manufacturer recommendations do not correlate with that curve of the light spectrum. Some manufacturers put as much as five times as much red light as blue light. I would be curious to hear what others have to say on that subject that is also near and dear to me.

 

[GodOfPot]

Hey this is a great question. Blue light has been shown by science to reduce plant size especially in veg so if you want explosive results try starting with red 100%, white 100% and blue only on a little bit, and turn on blue as plants go into flower to get those extra photons.

In my experience with dimmable LEDs it's best to have it using at least 50% power at all times and hung very high above your plants or else it will take a long long time for your plants to get used to the extra light. To your plant when the light is hung high it is a strong intensity but has less light coming from one angle which can burn your plants, it comes from all angles so your plant gets used to the "high" amount of light but doesn't get burned.

I'm under the impression that blue light has been shown to be very good for cannabis in veg stage while as red light is better for them in flower stage. I've never seen that it will reduce their size, in fact it will increase their growth and is basically the most important color in the early stages of growing(blue light).

 

[GodOfPot]

What's your grow space?4'x4'? Because personally I don't see any reason to even dim this unless you're having heat problems or you're worried about power consumption, but even still it's only pulling 210w at full power.

 

[Scientific]

Growth differences with spectra is complicated area with lots of misunderstanding, folklore, and challenges to get meaningful test results (such as, when you change the spectra, are you also changing the overall intensity?)

A simplistic but possibly useful approach, short of doing actual experiments, might be just to turn all the lights on full blast, because cannabis loves light. I'm sure that idea will run afoul of some people's passionate "religious" (i.e. scientifically unsupported) beliefs about lighting as well as real science. My point is, there seems to be an awful lot of BS and folklore out there and not much scientifically validated information. (And if anyone does have some good, scientifically validated info on cannabis and light spectra, I'd love to see it!)

Just my .02 and musings... Interesting area.

 

[Jin Terra]

What's your grow space?4'x4'? Because personally I don't see any reason to even dim this unless you're having heat problems or you're worried about power consumption, but even still it's only pulling 210w at full power.

Thank you everyone for your feedback. I planned on posting my grow with updates but considering all the different angles I'm getting I think what I will do is grow the same strain using different light settings to see what the result is.

My grow area is 3.5 x 3.5 but... I'm going to reduce the area to 2 x 2 and grow one plant at a time using different light settings. I'll post each grow with a journal. I'll be starting in about two weeks. This will be my setup:

5 gal DWC
6" Netpot with hydroton clay pellets
Root riot plugs once seeds germinates
General Organics nutes
2 x 2 grow cabinet with maylar walls
6" fan for circulation
6" airstone powered by a 20w air pump

I'll post details once I get my grow going.

Overall though while the journey will be fun I just trying to see why they would put dimming capabilities on a grow light to begin with beyond just heat control.

 

[Jin Terra]

Oh and I'm not worried about how much power I'll be pulling. With everything plugged in I'll be surprised if I pull more than 250w. That's about half of what a fridge pulls.