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red spectrum fluorescents for flowering?

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upanishad View Drop Down
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  Quote upanishad Quote  Post ReplyReply Direct Link To This Post Topic: red spectrum fluorescents for flowering?
    Posted: 09 May 2005 at 11:27
Hi there,

I am just setting up a grow room (well, cupboard). I see there are some new fluorescent lamps available which give out light in the red/orange spectrum (the brand I have seen is Envirolite). The Hydroponics site is marketing them specifically for for the flowering stage of growth (as opposed to the blue/white fluorescents for the grow stage). These lamps have some big advantages if they are suitable, principally they do not get too hot (I have a small enclosed space), they use less power and do not require a ballast.

The big question is, are they suitable? Does anybody have any experience or comments to make regarding use of these lamps for flowering? Also any comparisons? the flourescents come in 125w and 200w types, how do these compare to 400w standard grow lamps?

Another question I have, I am growing a sativa (silver haze), it continues to grow through the flowering stage, now once I start the flowering stage, should I keep my ordinary blue white flourescents on IN ADDITION to the orange spectrum lights, I would guess the more light the better? no?

Thanks in advance,

Uppy
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Ganja View Drop Down
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  Quote Ganja Quote  Post ReplyReply Direct Link To This Post Posted: 10 May 2005 at 12:16

The new, giant compact fluorescents seem like a good choice for certain applications. But normal household fluorescents are fairly similar, and may work out cheaper

The advantages of fluorescent lights are as you mention - fairly good lumens-to-power ratio, very little heat, no ballast required.

In terms of the amount of light they put out, we're not sure if CF lights are much more efficient than normal fluorescents.

We just obtained a CF bulb, and according to its own specs, it produces 8000 lumens for 115 watts (just under 70 lm per watt). Others we've seen are rated at 10k lm for 125w (80 lm/watt). Not sure about the 200w models, but we'll assume that they're in the same range.

A standard flourescent (120cm), available from any hardware store runs a 36w tube that produces 2800lm (78 lm/watt). Other 36w tubes may produce 2500 lm (just under 70lm/w , same as 115w CF), and newer ones may reach 3000lm (83lm/w).

You can get 36w/120cm tubes in warm (more red) and cool (more blue), plus daylight (close to a full spectrum). There are also tubes made by 'Grolux' and other companies that are specifically designed for indoor growing.

You can definitely grow with fluorescents, but the potential of your plants will always be less than if you grew under HID lights, simply due to the reduced amount and intensity of light that hits your plants. As a comparison, a 400w HPS produces 55,000 lm (137.5 lm/w), while a 600w is rated at 93k lm (155 lm/w).

Whether the new CFs are more suitable for indoor growing than standard fluoros is a matter of debate. The CFs are smaller than the 3 or 4 120cm tubes they could replace. On the other hand, standard fluoros can be mounted vertically up walls or in corners of very small grow-closets. for effective 'all-round' lighting. CFs are best used in the middle of the room (probably hanging vertically).

If flowering with fluoros of either type, it's best to have all-round illumination, rather than light from a central point. Elsewhere in the forum, 20' Thai mentions that plants grown in fluoro lights produce less resin than sun or HID-lit plants, particularly on those parts of the plant that aren't directly illuminated by the fluoros. Reflected fluoro light may be enough to see by, but it has lost so much intensity that it is of little use to flowering plants.

CFs are more fragile than standard fluoros. The tubes of both types are equally fragile, but standard tubes can be replaced when broken or old, whereas CFs have their tubes built-in to the ballast/fitting at the bottom (they're usually made up of  four or six 'u' shaped tubes). If one tube breaks or wears out, you'll need a new CF.

Since neither give out much heat, both produce a comparable amount of light, and both are available in the different spectrums, whether to use CFs or standard fluoros can be decided on your budget, growing space and maybe the availability of replacement lights.

Regarding your last query, it's best to have as much light as possible, especially in the flowering stage. Try to keep a ratio of 2:1 or 3:1 with red:blue light in flowering.

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upanishad View Drop Down
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  Quote upanishad Quote  Post ReplyReply Direct Link To This Post Posted: 10 May 2005 at 14:54
A big thanks for that. Excellent information that is really helpful to me at this startup stage.

The impression I had from the Hydroponics shop was that these CF lights had been specifically designed for growers and have a light spectrum that has been tailored to the requirements of the flowering plant and that they were not the same as the standard warm fluorescents.

I think the crux of your statement is that even if this were so, you can get close enough to a suitable spectrum with warm fluoros and the more important factor is the light intensity and distribution. As you say, these CFs produce around 10k lumins at 125w. One thing to keep in mind regarding the lower light intensity of the CF/fluoro tho is that because the lamp is not hot, you can place it very close to the plants and this may go some way to compensate for their lack of intensity, no?

I have a tall thin cupboard, 1.5m x 0.7m x 0.5m, ideal for shutting out light, but difficult to ventilate, hence the fluoros.
I have 3 5ft, 58w strip flouros positioned diagonally (top to bottom) across the back and two side walls of the cupboard and I will hang a single red spectrum CF from the top and vary the height so it is always close to the top of the plants. This setup gives a good distribution of light, even tho it is low on intensity (25k lumins max).
After reading your reply, I realise I can simply have both red and blue tubes available, and simply sspranos them over at the different growing stages to get a more suitable light spectrum.

Thanks once again,

uppy
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  Quote Ganja Quote  Post ReplyReply Direct Link To This Post Posted: 10 May 2005 at 15:37

The give and take of fluoro lighting is just as you outline.

They have a good light-for-power ratio, poor reach in terms of how far useful light travels, but the advantage of being able to almost touch the plants they're illuminating without burning them.

CFs have been designed with different colour spectrums in mind, but I think this is fairly similar to the different light colours in standard fluoros. For instance, the 'complete spectrum' CFs I've seen have 2 of the 4 'u' tubes in the blue range and the other 2 in the red range.

Also, Grolux tubes have been specially designed for growing and are available in 34w/120cm. I'm not sure if you can get them in 58w/150cm.

Your plan of strip fluoros around the sides, plus a CF in the centre sounds like a good solution. You'll get a lot of light with minimal heat and not too much power consumption.

I'd think about using the 200w CF if you can, or possibly even 2 x 125w CFs (both red). This way you'll be using just under or just over 400w of power for lighting. This should give you 25k to 35k lumens in this small space, which should be enough light for good, solid buds.

Finally, bear in mind that the top halves of your 5ft fluoros will be providing light for the top half of your cupboard and will illuminate the space as a whole, but will not provide useable lumens to plants on the floor. You could put some shelves in the upper reaches of your cupboard so that smaller plants can use this light.

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