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Randalizer

Effects of differing wavelengths of light on cana growth.

175 posts in this topic

If using uvb remember to cover your arms and cover your eyes when working with the girls or just turn the uvb off

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If using uvb remember to cover your arms and cover your eyes when working with the girls or just turn the uvb off

Cheers groovelick. After a bit more reading on here, think I'm just gonna ditch the UVB option and just stick with the MH for last couple of weeks of flowering - what u think? Does UVB really give you a noticeable difference in quality of smoke?

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There are some nice, compact and easy to add super-twist cfl reptile lights with the standard E27 screw-in base, "Repti-Glow" with various gradients of UVB.

Great infos collected here. folks! It is mostly in line and confirming what I have researched or experienced. Good to break up the hps myths and the notion that only red in flowering is the only way to go - after all, the sun offers all the wavelengths through the whole life cycle - it doesn't shut off the blue wavelengths just because certain plants are flowering ;-)

Blue wavelengths during flowering will fill-out and fatten up the stretched calyxes from hps. The morning-noon-evening / red-blue-red routine is a good simple scheme to imitate nature. Can save energy too, if full-blast is only at high-noon. Plants in nature don't experience, instant-on full blast from dawn to full blast with instant cutoff at nightfall either, but rather a fade into and fade out off peak lumens. For those wishing to save energy and cut costs, it is helpful to think about light-cycle as one thing and peak illumination as another, entirely seperate issue.

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Cheers groovelick. After a bit more reading on here, think I'm just gonna ditch the UVB option and just stick with the MH for last couple of weeks of flowering - what u think? Does UVB really give you a noticeable difference in quality of smoke?

this is a post from GreenFloyd that i feel is accurate, has helped me with my whole understanding of spectrums. ive decided to go for a gavita light system now. check it out if u havent already seems promising

GreenFloyd stated.

"It's the UV-B from MH that increase potency in both, Indica and Sativa's.

Research by Ed Rosenthal stated something similar to Ot1 regarding the Blue spectrum for MH.

He states that it is the Far-Red light that causes stretching and Sodium bulbs don't emit that wavelength.

"MH were originally promoted as the light to use during the vegetative stage of the plants growth, before the plant is forced to flower.

But now it is generally recognized that plants grow just as well vegetatively under a sodium as under MH.

Since plants need red spectrum for photosynthesis, it's absence is felt when using MH." Ed

HPS (sodium) lamps support fast growth during veg and flowering stages. They need no supplementing during any stage of growth." Ed

"Cannabis is a high energy plant, some schools think the thc/resin glands developed to protect against intense shortwave light.

Halides provide that to some extent, but don’t compare to high altitude sunlight in the tropics." OT1

The only real benefit it appears from a MH is when used with or in-place of a sodium during the final two weeks of flowering. The UV-B from the MH greatly increases THC potency.

IF you only have one reflector, I would stick with the sodium as during the last two weeks your buds are still packing on the weight and density which the sodiums excel in.

If you can, add a UV-B reptile lamp in there during the last two weeks.

If you had two reflectors, stick a MH in one for the last two weeks."

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Possibly a stupid question, but has anyone tried light filters, or, say, putting blue cellophane on their tent walls during veg and red during flower? would that even make a difference? I used just a hps for veg and flower, never thought to try blue walls during the growing stage.

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Light doesnt work like that. If there isnt blue in the light the filter wont be able to add it.

Do a google for: newton two prism experiment

Edited by highgrower
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Great thread. I am an led grower but I plan to add some uvb during the last few weeks of flower.

There are so many LED Vs HID threads here and every other board but I like the idea of a combined LED and HPS, best of both worlds

The wave length and low heat of high output LED panel plus the heat (I'm thinking bare bulb so not too much) and the red high lumen output of HPS.

Could be an idea for people who want more light without too much heat

Just a stoned idea lol

Wizard

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Great thread. I am an led grower but I plan to add some uvb during the last few weeks of flower.

There are so many LED Vs HID threads here and every other board but I like the idea of a combined LED and HPS, best of both worlds

The wave length and low heat of high output LED panel plus the heat (I'm thinking bare bulb so not too much) and the red high lumen output of HPS.

Could be an idea for people who want more light without too much heat

Just a stoned idea lol

Wizard

I live close to some commercial greenhouses (tomatoes) , they use hps at the top and LED's on the lower plants ...... seems to produce hefty tomatoes :)

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Personally I would avoid UVB like the plague. It can improve THC yeild in certain strains but at the expense of metabolising all of the CBD.

By using a lot of UVB you could turn an 18%THC 10%CBD plant into a 19%THC 0%CBD plant, but I'm not sure you would really want to.

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Do you have a source for that info @@OldBeardo please?

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