Tweaking Artificial Lights

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Tweaking Artificial Lights

Post by Susan Dobb » Tue, 06 Mar 2001 12:28:42



Quote:

> I read a bit about about distances and flourescent bulbs and one thing I
> noticed is that
> my shop lights are less then 3 inches between the two tubes. I read that
> (per USDA study)  less then three inches from the
> center to the center of the two bulbs causes reflectance and light loss
> to heat. Does anyone use artificial lights set more then 3
> inches? Is it even a consideration?

Perhaps they meant 3" from the center of one bulb to the center of the
other?

FWIW, I did a lot of light gardening with fluorescents in the 70s and 80s
and I don't think that was ever an issue.  I was careful, though, to get the
fixtures fairly close to each other - so that a tray centered under one
touched the sides of the one centered under its neighbor.  That way, the
lights overlapped and raised the footcandles.  I also put foil down on the
table.

Susan in Monterey, CA

 
 
 

Tweaking Artificial Lights

Post by Susan Dobb » Wed, 07 Mar 2001 00:15:46


Quote:

> Yes, They meant that. Mine are 2.75 inches.

> I was wondering about the foil you mentioned. Reflectance back up at the
> underside of leaves (though that light is diffused) grows better? I'd like to
> close the area in with white painted sides, though I could use foil. Flat white
> paint is nicer, though I am unsure of the benefits.

You can buy mylar in rolls for that purpose, at places that sell hydroponic stuff
or mail order.  At the time, I couldn't afford that, so I used heavy duty foil.
:)  Since we moved a lot, I had many versions of the indoor garden; the one I liked
best was in front of a big window, so it got both kinds of light.  Another big help
was blocks made from s***wood.  I could move the lights up and down by adjusting
the hooks on chains, but there was a lot less of that once I figured out that the
trays could be put on various combinations of blocks.

Have fun!

Susan

 
 
 

Tweaking Artificial Lights

Post by Kay Cange » Wed, 07 Mar 2001 00:57:46


Quote:

> Yes, They meant that. Mine are 2.75 inches.

> I was wondering about the foil you mentioned. Reflectance back up at the
> underside of leaves (though that light is diffused) grows better? I'd like to
> close the area in with white painted sides, though I could use foil. Flat
white
> paint is nicer, though I am unsure of the benefits.

If you know somebody who runs marathons or other distance events, they
often give out shiny 'space blankets' at the end. I picked up a couple at a
10 miler a few years ago and tried them over some lights. Beats me what
they are made of - mylar or tyvek possibly.

--
Kay Cangemi

A chiel 's amang ye takin' notes - Burns

New York, USDA zone 5
http://www.ulster.net/~cangemi

 
 
 

Tweaking Artificial Lights

Post by BeeCroft » Wed, 07 Mar 2001 11:39:19


Somewhere I read that flat white paint was 3% more reflective than was aluminum
foil.
I know sheet metal in the sun gets pretty darn hot so I am inclined to believe
it.
Anybody got a camera with a lightmeter for a quick test?
Taliban's supreme commander, Mullah Mohammed Omar can kiss my ass.