5k lumens from directly under the bulb or overall output? (T5 HO 54W)

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CannaZen

Member
Hi all, i was hoping you could clarify this for me.

I've noticed that standard 24W 2ft HO T5 bulbs are rated to output about 2k lumens and nearly doubles with extended bulbs and therefore wattage. (4ft-54w bulbs)

As known 54W HO T5 bulbs are rated to output about 5k lumens. My question is as you may have gathered from the title, Is this output based from the entire length of the bulb overall or as measured from directly under the bulb?

Thank you.
 
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RM3

RM3

Well-Known Member
As a grower that uses T5's to flower with, I gotta ask,,,,

why does this matter? since lumens mean absolutely nothing to plants ?
 
C

CannaZen

Member
It matters to me as a buyer. I'm only a newbie but lumen output does give indication of brightness and to me that may give indication to performance.

I realize T5 may produce excellent results but the reason HID can be of a greater distance from the plants is through Lumen output. I'm afraid i dont understand how brightness does not make a difference to the plants unless the transfer is thought of in terms of internet bandwidth or electrical amps.
 
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C

CannaZen

Member
RM3 said:
nope, it doesn't

as I said been flowerin with T5's for years, have tested many bulbs, lumens mean nothing
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And yet that statement means nothing to the context of this thread, its been said before elsewhere.

A 13watt cfl bulb may as well have the coverage of the sun.
 
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whitebb2727

whitebb2727

Well-Known Member
Lumens are the measurement of how the human eye see light not plants.

Yes it is under the bulbs and it is cumulative only where the light path over laps.

What exactly do you need to know?
 
whitebb2727

whitebb2727

Well-Known Member
It is also generally measured at a given point under the bulb not in lumens though. It is more complicated than that and more lumens doesn't equate to better light.
 
C

CannaZen

Member
RM3 said:
I've only grown for 44 years and have written 2 books on growing and have spent many years trying to teach newbies

good luck
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I apologize, thank you for your time.


whitebb2727 said:
Lumens are the measurement of how the human eye see light not plants.

Yes it is under the bulbs and it is cumulative only where the light path over laps.

What exactly do you need to know?
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whitebb2727 said:
It is also generally measured at a given point under the bulb not in lumens though. It is more complicated than that and more lumens doesn't equate to better light.
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Thank you, i believe that has settled my inquiry. It would be very helpful if it can be explained how the plants see and absorb light in volume, i am not sure what is indicative of performance if brightness may not be considered (assuming lumens indicate brightness for the eyes)

Is Par a good reference for this?
 
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whitebb2727

whitebb2727

Well-Known Member
CannaZen said:
I apologize, thank you for your time.






Thank you, i believe that has settled my inquiry. It would be very helpful if it can be explained how the plants see and absorb light in volume,i am not sure what is indicative performance if brightness may not be considered (assuming lumens indicate brightness for the eyes)
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COB are more efficient and will take less watts to get the same performance as t5.

I use a 432 watt 4 ft t5. It will grow 3-4 foot plants. A 12 bulb one would be plenty.

Break it down to what you want or need. T5 will be harder to cool. Is your electric cheap? Mine is so its been hard to spend the money on cobs.

I prefer mixed spectrum weed. I plan to use cobs in the future but will still use a couple t5 bulbs.

It basically breaks down to t5 is cheaper up front but more costly to run and cob is cheaper to run but cost more to setup.
 
C

CannaZen

Member
whitebb2727 said:
COB are more efficient and will take less watts to get the same performance as t5.

I use a 432 watt 4 ft t5. It will grow 3-4 foot plants. A 12 bulb one would be plenty.

Break it down to what you want or need. T5 will be harder to cool. Is your electric cheap? Mine is so its been hard to spend the money on cobs.

I prefer mixed spectrum weed. I plan to use cobs in the future but will still use a couple t5 bulbs.

It basically breaks down to t5 is cheaper up front but more costly to run and cob is cheaper to run but cost more to setup.
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I'm glad you brought up spectrum as I'm actually considering this for a broader ranges of terpenes and cannabinoids (via powerveg bulbs) but I've seen comparable or better results with cobs in terms of resin & size and that is (also) what my concern is for my small grow space, This I've attributed to light intensity. (lumens?)


I think i have gathered all that i can from this thread. :peace:
 
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whitebb2727

whitebb2727

Well-Known Member
CannaZen said:
I'm glad you brought up spectrum as I'm actually considering this for a broader ranges of terpenes and cannabinoids (via powerveg bulbs) but I've seen comparable or better results with cobs in terms of resin & size and that is (also) what my concern is for my small grow space, This I've attributed to light intensity. (lumens?)


I think i have gathered all that i can from this thread. :peace:
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I use agromax bulbs. They are a lot cheaper than hortilux bulbs. I also use a 10,000k+uva full time.
 
C

CannaZen

Member
whitebb2727 said:
I use agromax bulbs. They are a lot cheaper than hortilux bulbs. I also use a 10,000k+uva full time.
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Their custom phosphors are much more affordable, i think i could try agromax bulbs. I'm still not entirely sure how T5 may be compared with Led than with lumen output and concentration of light as with par. If T5 does not put out more light (Lumens) in greater concentration (Par) then i believe it may not be more efficient, I think it is much like voltage and amps making up wattage and therefor efficacy through brightness.

As a potential buyer I'm trying to make an informed decision, i do not intend to have this as a LED VS T5 discussion. I've just noticed that the lumen output seems to double from 2ft to 4ft bulbs when the extra wattage appears more related to the extra length of the bulb more so than a higher output within the same initial 2ft.
Instead If i understand correctly then the added lumen output is of the overall output of the entire length of the bulb and i now realize that was obvious, i'm sorry for putting it in such a way but i found it hard to arrive at that distinction.

A 12 bulb setup may give 24k lumens per 2 feet of the fixture at a foot or so away from the plants i guess. I believe cob chips might give better light penetration through light concentration and output of a smaller circumference.

I know this is a crazy arrangement but what would you think of this veg to finish?
UV, Par, bloom, 10k-UVA, par, bloom, UV, 10k-UVA, Bloom, 10k-UVA, Par, UV
(3 bulbs of each type)


I'm hoping this arrangement may lead to much more resin production with this ratio of UV.
 
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whitebb2727

whitebb2727

Well-Known Member
CannaZen said:
Their custom phosphors are much more affordable, i think i could try agromax bulbs. I'm still not entirely sure how T5 may be compared with Led than with lumen output and concentration of light as with par. If T5 does not put out more light (Lumens) in greater concentration (Par) then i believe it may not be more efficient, I think it is much like voltage and amps making up wattage and therefor efficacy through brightness.

As a potential buyer I'm trying to make an informed decision, i do not intend to have this as a LED VS T5 discussion. I've just noticed that the lumen output seems to double from 2ft to 4ft bulbs when the extra wattage appears more related to the extra length of the bulb more so than a higher output within the same initial 2ft.
Instead If i understand correctly then the added lumen output is of the overall output of the entire length of the bulb and i now realize that was obvious, i'm sorry for putting it in such a way but i found it hard to arrive at that distinction.

A 12 bulb setup may give 24k lumens per 2 feet of the fixture at a foot or so away from the plants i guess. I believe cob chips might give better light penetration through light concentration and output of a smaller circumference.

I know this is a crazy arrangement but what would you think of this veg to finish?
UV, Par, bloom, 10k-UVA, par, bloom, UV, 10k-UVA, Bloom, 10k-UVA, Par, UV
(3 bulbs of each type)


I'm hoping this arrangement may lead to much more resin production with this ratio of UV.
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The pure uv, just one can fry plants.
This is what t5 can do. I use one 10kuva bulb.
DSC00585.JPG
 
RM3

RM3

Well-Known Member
CannaZen said:
I know this is a crazy arrangement but what would you think of this veg to finish?
UV, Par, bloom, 10k-UVA, par, bloom, UV, 10k-UVA, Bloom, 10k-UVA, Par, UV
(3 bulbs of each type)
Click to expand...
Drop the Pure UVB from the list, ya can't run em continuously they need a separate fixture/timer

Check my sig link if ya wanna see what T5's do when spectrum is dialed
 
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