• Here is a link to the full explanation: https://rollitup.org/t/welcome-back-did-you-try-turning-it-off-and-on-again.1104810/

What type of light bulb can you leave on 24 hrs to view plants without disturbing it's bloom cycle?

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DarthBlazeAnthony

Well-Known Member
I have seen grow rooms with certain lighting that you can always see the grow. It must be a certain wavelength of light. I think it may be green. Does anyone know? Light leak in grow tents is always a concern for growers. I am curious if you can use a certain light outside the tent as to not disturb the plants inside.
 

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Getgrowingson

Getgrowingson

Well-Known Member
Don't leave it on 24 hours though. Just switch on when you want to work and off when your done. If left on 24 hours might cause problems
 
trevronious

trevronious

Well-Known Member
Same. I open my tent all the time at 'night', never had anything happen.

However, I'm not sold on the idea that green light makes it any different. Especially just a white cfl with some green filter on it. There are very specific wavelengths that are claimed to not be absorbed, 530nm I believe, in which you would need an LED with said nm of green to achieve. All green is not created equal. Still I'm not sold either way.



This to me shows activity all the way through.
 
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DarthBlazeAnthony

Well-Known Member
trevronious said:
Same. I open my tent all the time at 'night', never had anything happen.

However, I'm not sold on the idea that green light makes it any different. Especially just a white cfl with some green filter on it. There are very specific wavelengths that are claimed to not be absorbed, 530nm I believe, in which you would need an LED with said nm of green to achieve. All green is not created equal. Still I'm not sold either way.



This to me shows activity all the way through.
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Thanks for your informative response. The concern is not the plants going hermie but rather the buds not being as big as they could be. I don't know the effects of minimal light leak on bud growth. I am way too curious about this. If the tent is sleeping I try not to let in any light on the outside the tent. I hear crazy stories that we need to be careful of pinhole light leaks in tents. I am with you guys that light leaks have minimal impact. I really just want a night light outside the tent that will not disturb the plants inside. Outdoor plants endure moonlight so maybe that light wavelength could be beneficial and allow me to view my plants anytime without disturbing them.
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trevronious

trevronious

Well-Known Member
I would think since moonlight is just reflected sunlight you could equate that to a low intensity light small scale. I'd argue that since those green cfls are such a low wattage that is the real reason people think they don't harm the dark cycle for short periods of time. I'd just use a real small bulb if need be.

The green light thing has always baffled me. Using the logic the wattage shouldn't matter, just that it's "green". So what if you went in there with a big 150w green cfl instead? I'd be willing to bet you'd see a negative effect.
 
RM3

RM3

Well-Known Member
My garden is in my basement, it is not in a tent or small room, but rather wide open in a 500 sq ft room. My veg area is behind it and also wide open, my veg lights are on for 1 hour during flower dark time, there is a huge glow of light reflected on the walls. My base door stays open and at the top of the stairs is a window that faces west and gets sunlight every night that makes a large spot on the basement floor during lights out. It is enough light to be able to see to walk around in. I also have my freezer down there and the basement light is a 27 watt 2700K cfl, I turn it on all the time to take lights out pics, get stuff outta the freezer and I've been growing like this for years with zero problems

The whole light leak thing is a total myth

I also did the blue light for 24 hours a day in flower experiment mentioned in Ed Rosenthals last book with no problems, it did not increase bud yield so I stopped doing it

a 13 watt cfl will give you zero problems whether it is green or not, plants need at least 3000 lumens from a light source before they respond to it
 
bicit

bicit

Well-Known Member
Lots of weird info on this page.

DarthBlazeAnthony said:
Is there any light wavelength that we can see but a plant is unaffected?
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Short answer is, no. Even a 'green light' will effect plants. It's not absorbed as much as other wavelengths but it still does effect plants since it's used to drive photosynthesis rather effectively. It's an old urban legend that plants don't use green. However that's has been thoroughly debunked.

For working with plants after dusk just keep the light minimal and indirect. I've never had a hermi even when leaving the lights on accidentally, that's with a 68w(actual draw) CFL :P.
 
REALSTYLES

REALSTYLES

Well-Known Member
Ahhh let me put your mind at ease. Let's say you were growing outside and what happens when there is a full moon or a well lit star sky in nature does the outdoor plants hermie? No. I grow in multiple tents and for the very small amount of light leaking in I wouldn't be too worried and if you are just put a big blanket over the front to block the light you are afraid of leaking in.
 
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churchhaze

Well-Known Member
Theoretically, an appreciable intensity of green light should put %Pfr above 50%. It's at 0% when it's dark and a few hours have passed.


Judging by this chart, 555nm light will cause %Pfr to converge higher than 400nm-500nm would. Look how Pfr absorbs better than Pr between 400-500nm. This suggests that the range 400-500nm will cause %Pfr to be below 50%. Based on this alone, a blue lamp would interrupt sleep less than a green lamp would.

A 660nm lamp would obviosuly interrupt sleep the most bringing %Pfr to near 85%, while a 730nm lamp could bring %Pfr back to near 0%.

Honestly though, my advice is to keep all the lights out at night, and to visit your plants when the lights are on. Stop looking for ways to potentially ruin your crop.
 
trevronious

trevronious

Well-Known Member
PurpleBuz said:
wrong, sorry to be be hard on you but its well proven science that green light does not effect the flowering cycle of short day plants. Its like plant physiology 101.

if you apply very high wattage of green you may effect it, simply because the light may not be pure green light, and has small amounts of 580-750 nm wavelengths (especially poorly done party bulbs.)
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Green light is used. I'll continue to laugh at anyone who uses some magical green cfl thinking it does nothing.
 
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Eraserhead

Well-Known Member
If green and yellow doesn't do anything to plants, why does HPS work so well? And the red and blue only Chinese LED panels that have more red and blue than an HPS of a much higher wattage than the LED, not grow so well?

The reason those green bulbs work well for viewing during "lights off" time, they emit practically no photons, especially if they're multiple feet away from the plants.

I use the orange colored CFLs, 13w, in my home when I want very little and relaxing light. It's a lot like candle light. I'm gonna take some PAR measurements off of it. I'm willing to bet at 18" from the bulb, it has less measurable light than what the full moon has.

Next full moon, and a clear night, I'll take my spectroradiometer outside and get some measurements.

I took a picture of Jupiter a few weeks ago:

And one of the moon on the same night:
 
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