Subject: Re: indoor fluorescent lighting

From: [email-masked] (Stan)
Date: Sun, 12 Mar 1995 16:48:15 GMT

<[email-masked]> <[email-masked]>
Organization: IQuest Network Services
X-Newsreader: WinVN 0.91.6

In article <[email-masked]>, [email-masked] (Kevin Crader) says:

 >Just got back from the Arnold Arboretum, where alot of cool woodies are
 >propagated via all techniques. One of the propagators told me, as far as
 >growing from seed is concerned, they used to recommend a mix of warm and
 >cool bulbs. Now they recommend cool white alone (although you can still
 >use both if you want) for the home propagator. In their considerable
 >growing experience they have seen *no* difference whatsoever. Use the
 >savings to buy more plants!
 >
 >Kevin

hey Kevin,

what the propagator said is probably right as far as the lamps
they used.  using ordinary commercial home/office lighting,
whether cool or warm, is *not* the same as using colour
corrected lamps designed *specifically* for horticulture though.

The headings of "cool" and "warm" are general statements used
by the lighting industry, which when i started indoor gardening
about sixteen years ago, i used in combination, and later switched
to just cool white lamps.  but continueing experimentation, and the
advice of _experts_ in the field of horticulture (specifically indoors
under lights) has lead me to the use only lamps designed for
horticulture when i am trying to grow plants.  i too did not notice
much of a different between a mix of cool and warm normal lamps
over just cool white, but *i* definately have noticed a heathier/more
robust seedling (yielding significantly more in the end) using lamps
specifically made to grow plants.

Stan

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From: [email-masked] (Dawn Burgess)
Date: 12 Mar 1995 18:41:24 GMT

In article <[email-masked]>, [email-masked] (Kevin Crader) says:
[Argument that plain fluorescent tubes work fine for plants deleted]

Then, In article <[email-masked]> [email-masked] (Stan) writes:
[Argument that special grow lights are needed deleted]

Just another datum.... Stan says that the professional growers Kevin
talked to must have meant "horticultural cool whites" when they said 
"cool whites."  Not necessarily.  Some growers must think grow lights 
work better (since someone must buy them!), but not all of 
growers think that.  I was at Orchard Supply
Hardware, and one of the managers there (who would have every reason to 
want me to buy the grow lights, since they were *50* times more expensive--
no kidding!) said "well, I have run a greenhouse for years, and I find that
these work just fine."  He directed me to the plain fluorescent tubes
that were on sale for $.49 each.  I bought 2 :).  My plants are doing quite
well (brandywine tomatoes, ancho peppers and tomatillos).  I have
the lights only an inch or two from the leaves.  If your plants are 6" from
the lights, they are getting only 1/3 as much light as they would if 
they were 2" from the lights.  Fluorescent lights aren't hot, so don't
be afraid to really get 'em close.

Dawn

---

From: [email-masked] (Kevin Crader)
Date: Sun, 12 Mar 1995 22:08:10 -0500

In article <[email-masked]>, [email-masked]
(Dawn Burgess) wrote:

 I was at Orchard Supply
> want me to buy the grow lights, since they were *50* times more expensive--

Yes, they are *very* expensive. Case in point - I bought a 20" 15W
Vita-Lite for my pet turtle so she can have full-spectrum during the
winter, and that sucker set me back $25!!!

If money is no problem then HPS (high-pressure sodium) is more efficient
than floures. with higher output- but the lamps are about $250. and the
bulbs $15. "Similar to Gro-Lux and other color improved floures. compared
on equal energy" USDA sez...

Kevin

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From: [email-masked] (Lynn Edwards)
Date: 12 Mar 1995 19:32:13 -0800

Dawn Burgess ([email-masked]) wrote:
: In article <[email-masked]>, [email-masked] (Kevin Crader) 
: says: 
:    [Argument that plain fluorescent tubes work fine for plants deleted]

: Then, In article <[email-masked]> [email-masked] (Stan) 
:  writes:
:    [Argument that special grow lights are needed deleted]

: [story about Orchard Supply Hardware, who  says that ordinary cool whites 
:  are just fine deleted...]

I've used fluorescent lights for many years to get a head start on 
springtime for my tomatoes and peppers.  I've used cool white (cheap) 
tubes as well as vita-lite and glow-lux (expensive).  I've used them side 
by side while comparing results with as much care as can be reasonably 
expected (without goverment funding, anyway).  The end result:  I can't 
document any difference between them.  The grow-lux and vita-lite bulbs 
did not do any worse than the cheap tubes, but they didn't fare any 
better either.  My advice currently is to use the cheap ones.  Why spend 
the extra money?

I'm not a commercial gardener, but I am not a novice either.  My 
vegatable garden is 1300 square feet, and this year I will be growing 55 
different varieties of peppers (spanning 9 species, 165 plants total) and 
16 kinds of tomatoes.  

I couldn't find any references in the many gardening books that I own that 
claimed that the expensive lights were required - and quite a few said they 
were unnecessary.  My books are not specific to a particular growing 
philosophy.  I like to read from all sources - from Organic Gardening to 
Ortho's publications.  It seems that the connection between full spectrum 
tubes and healthier seedlings is weak, from the info I have and my own 
experience.

In that vain I would be interested in hearing other exeriences, both pro 
and con.  Any reference to controlled studies would also be warmly 
received.

Also, please note:  I use fluorescent lighting for seedlings only.  I 
found several references saying that full spectrum tubes were necessary 
for flowering, setting fruit, and making viable seeds.  

---Lynn Edwards
   Los Altos, California, USA

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From: [email-masked] (Stan)
Date: Mon, 13 Mar 1995 13:36:45 GMT

<[email-masked]> <[email-masked]>
Organization: IQuest Network Services
X-Newsreader: WinVN 0.91.6

In article <[email-masked]>, [email-masked] (Dawn Burgess) says:

>.... Stan says that the professional growers Kevin
>talked to must have meant "horticultural cool whites" ...

after re-reading my post... i find i said nothing of the kind.
in fact, i was trying to imply the opposite, that the growers
that Kevin talked about probably meant non-horticultural lamps.

---

From: [email-masked] (Stan)
Date: Mon, 13 Mar 1995 13:59:38 GMT

<[email-masked]> <[email-masked]> <[email-masked]>
Organization: IQuest Network Services
X-Newsreader: WinVN 0.91.6

misrepresentation of what i am saying is nothing i have
control over, but for the record:

- i never said that colour corrected flour. lamps are *required*

- i was not making my recommendations based on cost, and if cost
is your number one concern, then don't even think about lighting
designed specifically for horticulture

- my objectives in gardening is getting maximum yield of the
highest quality fruits and vegetables possible.  in order to
achieve this, *i* have found that using specialized lighting
has produced better final yield... albiet, my techniques in all
areas have improved, thus providing an overall improvement.

- Lynn, i have found a one day difference in plant seedlings
has equated to more that a 25% differnece in final harvest
weights of some veggies at the end of the season.  Lighting is
only one factor (and a small one at that) that effects initial
seedling growth.  as mentioned in previous post, my main thing
is indoor gardening (start to finish), and finishing plant height
is a critical factor to me.  when using just plain cool whites,
i consistantly ended up with taller (not desireable) final plants
even when the lamps were only 1/2 to 1 inch above the seedlings.

- my goal is not to get people to switch to *expensive* grow
lights.  I like what *i* use (as much as others like what they
use) for whatever reason, and i answer post referenced to my
gardening experience.

Stan

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From: [email-masked] (Birdmommy)
Date: 13 Mar 1995 10:57:40 -0500

the vitalite might have set you back a bit for the turtle, but look at the
bright side, (grin, no pun)  after you can't use it for the turtle any
more (I think they recommend replacing them yearly, the light not the
turtle) you can use it for your plants!  I'm on year three with my 40"
ones and my plants just LOVE them!

molli
Denver zone 5

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From: [email-masked] (Bill Pulliam)
Date: 13 Mar 1995 18:16:21 GMT

In article <[email-masked]> [email-masked] (Richard Campbell) writes:
[snip]
>
>   I don't disagree with any of this except for the fact that plants at 6"
>from the lights get only 1/3 as much light as plants at 2".  They 
>actually get much less than 1/3, I believe that they would get 1/9 as
>much light.  Doubling the distance from the light source quarters the
>amount of light received.

Not true if the lamps have reflective hoods that direct most
of the light downward and you keep them at close range.  The 
illumination still drops off pretty fast, but it is more like
a inverse proportion to distance, not square of distance,
so long as the distance from the hood is < half its width.

You should still keep your seedlings as close to light as 
possible -- I've been amazed at how much better seedlings grow
with lights 3" versus 6" from the tops of the soil!  They are
perfectly happy with their leaves touching the fluorescent
bulbs directly.

Bill

---

From: [email-masked] (Dawn Burgess)
Date: 13 Mar 1995 19:12:52 GMT

In article <[email-masked]> [email-masked] (Richard Campbell) writes:
>
>In article <[email-masked]>, [email-masked] (Dawn Burgess) writes:
>|> the lights only an inch or two from the leaves.  If your plants are 6" from
>|> the lights, they are getting only 1/3 as much light as they would if 
>|> they were 2" from the lights.  Fluorescent lights aren't hot, so don't
>|> be afraid to really get 'em close.
>|> 
>

True, if the lights were a point source.  I think they are closer 
to a line source, though, which I think should go as 1/r, not 
the inverse square.  I could be wrong, though, since someone else
mentioned the effect of the reflective hood.  But that should 
decrease the distance effect, not increase it.  Dang, what ever
happened to the spherical cows of classical mechanics?!  :)

Dawn

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From: [email-masked] (David M. Davis - Public Safety)
Date: 24 Mar 1995 11:16:28 GMT

I found a pamplet from the Isreali Agricultural ...  that talked about
growing under flouresents. My local greenhouse pro said bad idea, even
if the Isreali's did it. I haven't been able to try it yet.

The pamplet was in the Oregon State University Library.

David Davis
[email-masked]

---

From: [email-masked] (David M. Davis - Public Safety)
Date: 24 Mar 1995 11:16:28 GMT

David Davis
[email-masked]

---

From: [email-masked]
Date: Sat, 1 Apr 95 22:55:10 -0500

>if the Isreali's did it. I haven't been able to try it yet.
 
I disagree, I grow peppers and other plants through the winter with flouresent
lights.  They may not work as well on some plants but I think it's worth a try.