I have a gloxinia, a hydrangea and a few other indoor plants on a plant shelf
in the living room. I've been using a fixture with dual 40 watt Gro-lights
over them for years now, but it's not real great for getting some of the
plants that require more full sun, to bloom.
What other kinds of lights are available, that won't bust the budget or use
massive amounts of energy, but will simulate direct bright sunlight better?
- Popcorn Lover
If you love popcorn too, there are no popcorn groups on usenet but
I have read that Gro-Lights aren't any better than standard fluorescent
bulbs. Maybe you just need a fixture with more bulbs (or higher output)
that is closer to the plants. The amount of energy received by the plants
is inverse to the square of the distance to the source. Moving the fixture
closer to the plants will significantly increase the amount of light energy
they receive. In aquariums, especially heavily planted ones or reef tanks,
people are using high output fluorescent fixtures and/or metal halide
(mercury vapor) lamps. I would probably look into the high output
fluorescent bulbs as they are more efficient and don't produce large amounts
of heat. Here is a link to a search:
Wow, why don't you tell me how much better the grow lights are than standard
fluorescent bulbs? While you are at it, why don't you compare the
gro-lights to the high output fluorescent lights and metal halide lights
that I suggested the OP consider?
The problem with your request is that sunlight *is* much more intense than
any normal indoor light. You could up the ante to 8 bulbs instead of 2.
There are other fluorescent alternatives to Gro-lite bulbs, some may look to
the human eye to be more like sunlight but I doubt the plants would grow any
I've heard of people growing plants under mercury vapor or high pressure
sodium lights -- the kind of things used for streetlights or security lights
That's true when your light comes from a single point, but if it comes from
a 4' tube and you're already closer than 4', intensity varies inversely more
like with the distance, not the square.
Yes, with fluorescents you can put the lights right on top of the plants.
Not touching, because contact would interfere with aspiration.
-- spud_demon -at- thundermaker.net
The above may not (yet) represent the opinions of my employer.
The fixture you have is probably OK if you change the ballast to a
electronic ballast for F32T8 lamps, and you want one with a fairly high
ballast factor. The lamps to use are GE's F32T8-SPX35 or Philips
F32T8/ADV830/ALTO (or something like that). The ballast should cost
between $15 and $25, and the lamps are about $3 each. Forget "warm
white" and "cool white", and "use 1 warm white and 1 cool white bulb";
that was good advice 30 years ago but not anymore. The EPA screwed up
40W fluorescent bulbs really bad in 1978 (that's why you can't find a
good 40W lamp anymore.) Maybe 10 of 15 years ago the industry came up
with the triphosphor lamps and electronic ballasts used in T8
technology, and it's much better than the T12 40W lamps used to be, and
the lamps use less mercury.
It would be better if you had 3 or 4 lamps instead of just 2, but these
32W lamps will put out more and better quality light than any reasonbly
prices 40W lamps, and they don't dim as much over their lifetime.
You might look at a commercial electrical supply store for a "troffer"
style 4' fluorescent fixure for suspended ceiling that can take 3 or 4
F32T8 lamps. Especially if you buy a 4 lamp fixture, tell them you want
"high light output" rather than energy saving; a good 4-lamp fixture
should have 2 ballasts in it instead of just 1 (last time I checked
anyway.) you can suspend a troffer fixture from chains like a shoplite,
but it's 2 feet wide instead of 8" wide so it gives more even light
If you are serious about growing plants indoor, then there is no
comparison to a HID lighting system such as a HPS (High Pressure Sodium) or
MH (Metal Halide) system. The general rule of thumb for growing plants
indoors is 50 watts of light per square foot for plants that require full
sun. The problem with flourescent grow lights is that they just don't put
out enough light intensity to grow large plants. A HID (High Intensity
Discharge) system such as HPS or MH put out a very intense light. This
allows you keep the light source (bulb) several feet away from the plant
while still supplying the plant with enough light. In order to achieve
similar results with flourescent bulbs, generally you need to keep the bulbs
no further than 1" away from the plant at all times. This requires you to
constantly adjust your lights as the plants grow. Most plants grown under
flourescent lights will be long and leggy as they are trying to get closer
to the light source, due to the fact that their isn't much light intensity
coming from the flouro bulbs. Plants grown under an HID system gererally
will be shorter and fuller plants with more blooms. One warning though, HID
systems can create alot of heat and will need to be addressed during
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