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what’s up with blacklight use ?

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budman View Drop Down
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  Quote budman Quote  Post ReplyReply Direct Link To This Post Topic: what’s up with blacklight use ?
    Posted: 19 August 2005 at 02:03
does any one know if anything good could come from the use of blacklights advantages / disadvantages ?
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impact View Drop Down
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  Quote impact Quote  Post ReplyReply Direct Link To This Post Posted: 19 August 2005 at 07:29
A tube black light is a basically a fluorescent lamp with a different sort of phosphor coating. This coating absorbs harmful shortwave UV-B and UV-C light and emits UV-A light (in the same basic way the phosphor in a fluorescent lamp absorbs UV light and emits visible light). The "black" glass tube itself blocks most visible light, so in the end only long-wave UV-A light and some blue and violet visible light pass through.

Blacklights do not produce the correct spectrum of light to grow plants.

The only lights that currently produce the required color spectrum of light to grow plants are the following;

Suitable for Growing:

Flourescent (Tube shaped)

Compact Fluorescent
(a flourescent tube with ballast included that screws into regular light fixture)

Metal Halide (MH) Best for Vegetative growth, but it doesn't contain all of the spectrum needed later during flowering for truly outstanding buds. the light shines a blueish/white color

High Pressure Sodium (HPS) Best for Flowering. Ok for Vegetative. shines a yellow/orange color. All can be purchased at your local home/lumber store.

Not suitable for growing:

Blacklight type flourescent lights.

ANY incandescent lamp
(if it screws into a regular lamp, it won't produce worthwhile buds). Exception, compact flouro mentioned above)

Halogen

Mercury Vapor
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budman View Drop Down
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  Quote budman Quote  Post ReplyReply Direct Link To This Post Posted: 19 August 2005 at 09:51
hey thanks for the reply , the information was very useful . next time i hear someone saying they use black light during their dark stages i will pass on the info.
                                                                              thx
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mrnice View Drop Down
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  Quote mrnice Quote  Post ReplyReply Direct Link To This Post Posted: 20 August 2005 at 14:43
Many growers around my way make the mistake of thinking that they can grow a plant with only a HPS this is not the case as ganja has mentioned as it doesnt contain enough of the blue spectrum during the veg stage to produce proper healthy plants. vice versa for the metal halide, I use a 400w son-t pia agro which can be used for both veg and flowering but if you favour a 600w then you will have to use both a hid and a metal halide as i dont think you can get a 600w agro
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Ganja View Drop Down
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  Quote Ganja Quote  Post ReplyReply Direct Link To This Post Posted: 23 August 2005 at 12:19

As yet, I haven't been able to find a 600w AGRO

True, it's good to have full-spectrum light for indoor cultivation, but since the growing stage is relatively short, especially for clones (often less than two weeks for people who buy clones,rather than making them), you could probably get away with using a 600w HPS for growing.

It's not a good idea to try to use a 600w HPS as the light for a mother room or permanent 18hr area, but you could do a couple of weeks of veg growth immediately prior to flowering.

If you want to add blue/white light to an HPS-lit room, regular (120cm) fluoros or the new CF bulbs are a good choice - they're relatively cheap to buy and run, they produce good amounts of blue/white light for the power they use, and they generate very little heat compared to an MH or HPS.

The only problem with fluoros is that their light does not travel very far from the bulb. Beyond about 1m from the light source, fluoro light is visible but does not contain enough energy for effective photosythesis. On the bright side, the fact that fluoros are cool means that you can have them very close to plants - almost touching.

As far as I know, 'black light' tubes produce only visible violet light, not UV. Sunbed tubes produce UV, which is why they're dangerous and have strict rules about exposure.

I don't think black light tubes actually radiate UV, or there would be restrictions on their use. That, or it's extremely low-intensity UV that doesn't travel more than a few centimetres from the tube.

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