Hi, look for a "Pulse-Start" system. Most hydroponics and indoor garden places DO NOT carry them, but pulse-start is a new technology that gives more lumens per watt, more efficient lamp operation, and much much longer usable lamp life.
Some aquarium places will carry the 400W pulse start ballast and equipment, but the kits can be purchased from businesslights.com, so that you can buy just the parts for
any wattage you want, you just need to find a box to mount the stuff in. I bought 4 x 400 w pulse start metal halide ballasts. The lamps are also quite cheap, a standard Venture lamp will perform just a well as a "horticultural"
lamp for most purposes. The pulse start lamp has a different shape of arc tube which is more efficient and has a longer life. I also picked up 4 x 400w HPS ballast kits, and a few cases of hight output T8 lamps ($50 for case of 25) to run in my overdriven T8 bank garden. See my T8 pics in flickr.

Here is a link that might be useful: My T8 fluorescent shop light bank, and indoor garden pics.

I am currently using T-8 bulbs in standard 2 light flourescent fixtures. The bulbs are Philips F32/T8 2950 lumens, 85 CRI, and 5000K temp. I am using 5 fixtures (total of 10 bulbs) to cover an area thats about 6' X 6'. My palms and tropicals are doing fine I just thought I should go for more light if possible. I can't keep all the plants within inches of the lights but they all appear to be fine. In fact I have used this system for the last 2 years with good success. Does this sound like a good set up. What's your thoughts.

THANKS.

A 250W metal halide, of any variety, will not give you more light than you already have.

10xT8 (I'll assume 2600 lumens which is what you'll get on most ballasts) = 26,000 lumens

1x250W MH = 20,500 lumens with worse lumen depreciation

The light distribution will be different and that may suit your growing arrangements better. Or not. And of course you can use both systems at the same time, nearly doubling your light.

One thing I would suggest you look out for with this particular system is that it is "integrated". They make this sound like a good thing, but it means the ballast is in a single box with the bulb and reflector. Heat buildup is more of a problem. Most people opt for a remote ballast which is at the other end of a wire so that its heat is produced away from the bulb and away from the plants. It also means an extra 20lbs (more?) hanging above your plants.

I couldn't find an explicit mention in the auction listing but this is almost certainly a magnetic ballast. Anybody setting up plant lights these days should look for an electronic ballast, they are better in every way and will save you money on your running costs. Less heat, less waste, less electricity, more light.

Another thought is that your setup seems a little low on light for covering 36 square feet. Are you growing low light plants? Do you have some natural light?

I'd avoid listening to any of these people. Lumens are a measurement for the human eye, and have nothing to do with growing plants. Plants only care about the light that can hit the leaf, be assimilated, and make photosynthesis. It's called incident energy. If you see people using lumens as a standard of measurement, be sure they don't understand plant lighting at all. Photosynthesis stops on the leaf surface at 5500FC, the excess light is converted to heat. Buy an HID, forget the fluorescent,and try to make light that really resembles natural light.

Thanks for the responses.

Shrubs -the heads up on the electronic ballast is appreciated.
I'll make sure anything I buy has an electronic ballast. I guess I was under the impression that MH or HID just put out significantly better light than fluorescents and that light will be stronger at say 2-3 feet from the lights.

There is no natural light in the room (basement) and I am growing a few low light plants but am just interested in lighting that will provide a better environment for the palm trees.

Make sure your "electronic ballast" is FCC compliant. The cheap Chinese electronics everywhere in the market operate at a frequency that is broadcasting greater than an FM radio station. You can interfere with broadband, AM/FM radio, etc. Imagine your 60HZ on the wall, turning into 25,000HZ. Electronics are the future, just be very very careful what it is you purchase. Pay more and get more. Buy cheap, get a radio station.

FM operates at 87.8 to 108.0 Mega Hz, way way above 25 KHZ.

dcarch

Electronic ballasts do cause radio frequency interference. Mainly this is due to harmonics which are produced at multiples of the fundamental switching frequency. Modern ballasts, especially dimming ballast may operate at frequencies up to 100kHz. Any RF emissions above 10kHz are controlled to specified levels by the FCC. Other western countries have similar regulations. A small number of ballasts in use in your home are unlikely to cause problems unless they are illegal imports which do not meet regulations, although you will be able to find interference with a radio if you get close enough to the lights. You can get an indication of the level of harmonics by the THD figure for the ballast (lower is better, look for Almost every thing else written by dantjed is just the ravings of someone who spent too much time smoking pot when they should have been learning about the physics of light ;)

I think the two of them may be the same person posting under sparate I.D.s., if you know what I mean.

I noticed the claim about sunlight and high frequency. Very soon, he/they will be pushing spinning grow lights with 25w CMH bulbs.

dcarch

The thought did occur to me, but the gobbledegook of the two posters doesn't seem to overlap so I'm assuming for now that there are two different people. Dantjed just seems to be stuck in a bad acid trip from the 70's when fluorescents really were dramatically worse than metal halides as plant lights. But times have moved on, fluorescents have improved dramatically, metal halides only slightly, so the best choice now depends on the application.

"The thought did occur to me, but the gobbledegook of the two posters doesn't seem to overlap------" There is a medical term for that symptom.

All lights have there use for growing, depending on your particular situation. I am only against wax candles.

dcarch

Thanks. I appreciate the info.

Did you check my indoor T8 bank that I posted on another thread? I used 10 x T12 fixtures and replaced the ballasts with some very nice Chinese ballasts that are rated for the appropriate amount of current to properly ignite the lamps. I use Phillips Hight Output T8 that put out 3100lumen in stock form, and quite a bit more overdriven. I use a switch on the end of the fixture to allow me to overdrive on demand. A fluorescent bank acts like a "plate source" so the drop off of intensity with distance is not as severe as with a "point source", as long as the reflectors are good.
Also a fluorescent bank will allow a very even illlumination, much more even than a halide lamp.
Just because it's China doesn't mean crap. They do put out tons of cheap crap, but they also have high quality ballasts, that I was able to pick up really CHEAP on ebay, and they work perfectly.

Here is a link that might be useful: My T8 bank.

"Did you check my indoor T8 bank that I posted on another thread? I used 10 x T12 fixtures--------"

Very nice setup. Impressive work. You need to put on sun-blocker to work under those, LOL!

dcarch