Lights for indoor plants?

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?

Reply to
Popcorn Lover
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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:

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Reply to
Vox Humana

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 distribution.

Best regards, Bob

Reply to
zxcvbob

Wow, you're a regular spring of misinformation, aren't you!

Reply to
Bill

They appear to be somewhat better, because they have the spectrum that plants seem to like, but I'm looking for something that more closely approaches sunlight.

Yeah but gro lites just don't seem to have the intensity that full sun flowering plants need.

Thanks.

Reply to
Popcorn Lover

Thanks Bob, I'll check into it!

Reply to
Popcorn Lover

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?

Reply to
Vox Humana

If you really want to mimic the sun, you need high pressure sodium or metal halide, although they ain't cheap.

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Reply to
hal

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 installation. good luck, Matt

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Reply to
Matt

"Vox Humana" writes in article dated Sat, 07 Aug 2004 16:08:44 GMT:

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 better.

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 outdoors.

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.

Reply to
Spud Demon

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