# Thread: How many Cfls = 5000lumen?

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## How many Cfls = 5000lumen?

How many 23watt CFL's makes 5000 lumens?
and is 5000 lumens used when flowering?

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3. mmm between 3-4, and its 5,000 lumens per sq foot, do your floor print L x W (in inches) and divide by 12, times 5,000, thats how many lumens ya need

4. depends on the output of your CFLs.

and it's the more light the better!

-shake

5. Originally Posted by headshake
depends on the output of your CFLs.

and it's the more light the better!

-shake
true that, just a referance point, headshake i admire you, and your ghetto grows, represent whoop whoop

6. thanks stinky! i really appreciate that. i do what i can with what i've got to work with.

and you are pretty right on with your bulb number estimate, btw.

-shake

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Originally Posted by stinkybudz
mmm between 3-4, and its 5,000 lumens per sq foot, do your floor print L x W (in inches) and divide by 12, times 5,000, thats how many lumens ya need
hey, i've got 19x18inch space. according to your method, does that mean i need 142500 lumens?

8. Originally Posted by jonathanling
hey, i've got 19x18inch space. according to your method, does that mean i need 142500 lumens?
19" x 18" = 342 square inches

342 square inches / one square foot (12" x 12" = 144 square inches) = 2.375 square feet.

2.375 sq.ft. x 5000 Lumens = 11,875 total lumens

One (1) 23w cfl produces 1,550 Lumens (at least the one I was looking at, could vary a little, so adjust accordingly)

11,875 Lumens needed / 1,550 lumens per 23w cfl = 7.66.... so you will need at least 8 x 23w cfl's to reach over 5,000 lumens per square foot.

If you can keep the temps in range, I'd throw in a few more just for good measure

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ahhh, thanks a load dude

10. go here, click on your particular bulb, and read it's details ... shows lumens, life, etc... very reliable place to buy from, too (Texas company)
2 to 200 Watt Compact Fluorescent Bulbs : 1000Bulbs.com

Bigtopsfinn had it right, the 23-watters put out about 1600 lumens apiece, btw
Last edited by the image reaper; Apr-09-2009 at 18:08.

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That's one measurement of a much larger picture. Useful spectrum lumens received is really what you are concerned with. From Maijuana Horiticulture: The Indoor/Outdoor Medical growers bible, by Jorge Cervantes recommends 10,000 output lumens for a flowering plant. I have heard lower amounts used though. Also, different 23 watt bulbs have different lumen counts. Many variables

I would try using two 23 watts per square foot. 50 watts per square foot, while a very basic measurement, still works within the normally used lighting types like cfls and hids. But the more watts you can put it, and still keep it cool, the better off your plants will be.
Last edited by nomadinexile; Sep-07-2009 at 18:32.

12. Originally Posted by nomadinexile
That's one measurement of a much larger picture. Useful spectrum lumens received is really what you are concerned with. From Maijuana Horiticulture: The Indoor/Outdoor Medical growers bible, by Jorge Cervantes recommends 10,000 output lumens for a flowering plant. I have heard lower amounts used though. Also, different 23 watt bulbs have different lumen counts. Many variables

I would try using two 23 watts per square foot. 50 watts per square foot, while a very basic measurement, still works within the normally used lighting types like cfls and hids. But the more watts you can put it, and still keep it cool, the better off your plants will be.
i don't know why people use watts as a guideline for lighting in a grow room. watt has nothing to do with lighting specifically. watt is merely a measure of power consumed.

on top of that you give him a quote from a reputable source (jorge cervantes) of 10,000 lumens per/sq ft when flowering and then you interject with the 50 watts/sq ft comment.

if we are using 23W, ~1600 lumen bulbs that would give us well below the recommended 10,000 lumens/sq ft. it would in fact only get us ~3200 lumens, still below the MINIMUM recommended 5000 lumens/sq ft that most recommend.

i understand that lumen is not the best measure to use when making a decision pertaining to lighting, but is readily available on most packaging and an easier comparison than trying to get into watts. what if a bulb is more efficient than another, does the watt rule still apply? how does it apply to LEDs?

-shake

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I haven't used my brain in a while and it's a little dusty. You are correct. I will be more aware before I post in the future! Thanks.

Btw, I just got a "bright" white 23w for my inverts that is 1500 lumens. So using a baseline of 5000 desired output lumens, you would need 4 per square foot. (actually 6000)(of this brand and spectrum) IF you have everything else dialed in, and can cool 7/sq ft., you get 10500 lumens.

That's a lot of cooling. You would be better off imo going closer to 4 until you see you can keep temps in check. (relative to your experience, knowledge and equipment) Hypothetically you could run a space heater in there too and keep it cool, but most people won't pull that off!

Sorry again about the mistake, I will be more careful going forward. Peace

Originally Posted by headshake
i don't know why people use watts as a guideline for lighting in a grow room. watt has nothing to do with lighting specifically. watt is merely a measure of power consumed.

on top of that you give him a quote from a reputable source (jorge cervantes) of 10,000 lumens per/sq ft when flowering and then you interject with the 50 watts/sq ft comment.

if we are using 23W, ~1600 lumen bulbs that would give us well below the recommended 10,000 lumens/sq ft. it would in fact only get us ~3200 lumens, still below the MINIMUM recommended 5000 lumens/sq ft that most recommend.

i understand that lumen is not the best measure to use when making a decision pertaining to lighting, but is readily available on most packaging and an easier comparison than trying to get into watts. what if a bulb is more efficient than another, does the watt rule still apply? how does it apply to LEDs?

-shake
Last edited by nomadinexile; Sep-08-2009 at 22:57.

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## 100 watt cfls

I have 5 100 watt cfls in a 2'x2' space with 4 plants. Right now they are vegging. I just set up everything a month ago. I don't know how many lumens each cfl has, but it seems to be working. I'm going to see what happens in another month, hopefully by then I will be able to send some pictures. This is my first time growing under any kind of lights. Can't wait to see what turns out.

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Originally Posted by kushlvr
I have 5 100 watt cfls in a 2'x2' space with 4 plants. Right now they are vegging. I just set up everything a month ago. I don't know how many lumens each cfl has, but it seems to be working. I'm going to see what happens in another month, hopefully by then I will be able to send some pictures. This is my first time growing under any kind of lights. Can't wait to see what turns out.
I use 2- 26 watt 6500k per plant for veg and 1- 65 watt cfl plus a 42 watter both 2700k for flowering 1 plant and works great.Just for personal stash.Usually gets me a half oz that last me till next grow.

16. Lumens are pointless. Just stick to wattage as a guide.

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