Lumen ratings, coverage area

wordwizNovember 8, 2008

Does anyone know - bulbs are usually rated in lumens, such as 4,000 or 6,900 lumens. Is this basically the same thing as lux? I know lux is the amount of lumens per square meter (10.76 sq. feet IIRC) so does a rating of 4,000 lumens mean that the light if placed at a specific distance, one that would cover those 10+ sq. ft., that the lux reading would be 4,000?

Any links to data that explains this?

Mike

Thank you for reporting this comment. Undo
wordwiz

In another forum a member said he had read that the lumens quoted on bulbs are the amount reaching a surface from one foot away, or in other words, a ft. candle. To get it's lux rating, one would divide by 10.54 (I think that's the amount).

My light meter seems to agree. Taking the reading from about five inches away, I get ~14,500 lux. At exactly six inches, ideally I should get a reading of 13,800, at about two feet I get ~3,000.

IME, 3,000 lumens hitting the leaves of the plant should be enough for seedlings though not enough to set and produce fruit for most plants.

Mike

    Bookmark   November 15, 2008 at 11:51AM
Sign Up to comment
More Discussions
Energy efficient grow lighting
We are probably going to buying a nice heavy duty heated...
oldbat2be
My indoor garden setup - any improvements?
This is my proposed setup for my indoor garden. I'm...
gardev
HELP!..Possible Indoor Pepper growing probz!
I have a few questions regarding my pepper plants at...
Bobby Cooper
When to replace lights?
Hi, I have a 3-shelf cart with plant lights. I mostly...
frances_in_nj
New to Forum - some questions, comments about heating mats
I have been starting flower seeds indoors for years...
snapdrag
© 2015 Houzz Inc. Houzz® The new way to design your home™