fluros or mh and hps - Orchid Board

stef666 · #1 08-03-2010, 10:14 AM

hey there,Im just starting to build my new terrarium.Size is 1200mm (4ft)long 900 (3ft) high and 600mm (2ft) deep.Im intending to grow mostly high temp dendrobiums (bigibbum and the like) plus some vandaceous orchids)
It will be heated of course.
My question is because of the height of the enlosure what would be more suitable fluros or should i get some metal halide and hps lights.Just seems as though with fluros they may be too far away from the plants?

Any thoughts would be appreciated
cheers

trdyl · #2 08-03-2010, 02:09 PM

With the size of your space I think you'll be fine with fluros. They will also not generate as much heat as the others listed either which is a plus.

stef666 · #3 08-04-2010, 02:38 AM

So if i use the fluros how many would i need? its so easy with mh etc to say 500 watts etc but with fluros?

trdyl · #4 08-06-2010, 02:43 AM

With the newer fluros a 4 bulb 4ft T5 fixture will give you plenty of light which would be 216 watts.

This Side of Paradise · #5 08-06-2010, 04:20 PM

I have a tank that is almost the same dimensions with 5 4 foot t5 and im only getting 200fc at the bottom. If id have to do it again id get mh or hps

stef666 · #6 08-18-2010, 08:52 PM

Quote:

Originally Posted by cyberloach

I have a tank that is almost the same dimensions with 5 4 foot t5 and im only getting 200fc at the bottom. If id have to do it again id get mh or hps

thats was my concern.I dont really want to have my bigibums halfway up the enclosure although i could.

I was looking at an 8 x 39 watt light (ho) which is going to give me roughly 300 watts .... but then looking around as i do i saw the cfls where i can get say 3 or 4 200 watt ones.
Do the compacts still throw enough light evenly?

S-Smith · #7 10-04-2010, 05:20 PM

This is a good question, I have been pondering the use of t5's over a single 400w MH system, for my new orchid enclosure. I had been using a 600W HPS but I think it wasn't the right spectrum since my plants didn't seem to want to flower very much. I have read that since the t5's lumens are spread out along the bulb you don't get as much light penetration as a HID, also the HID still has better light output vs floros 400w=50k lumens I think, 515W of t5's equal this if I'm not mistaken. This is all speculation though I would love some real world results with both systems though to compare.

BioWheel · #8 10-05-2010, 12:09 AM

Quote:

Originally Posted by S-Smith

This is a good question, I have been pondering the use of t5's over a single 400w MH system, for my new orchid enclosure. I had been using a 600W HPS but I think it wasn't the right spectrum since my plants didn't seem to want to flower very much. I have read that since the t5's lumens are spread out along the bulb you don't get as much light penetration as a HID, also the HID still has better light output vs floros 400w=50k lumens I think, 515W of t5's equal this if I'm not mistaken. This is all speculation though I would love some real world results with both systems though to compare.

I'm using an 8 lamp - 4 ft long T5 system for my orchids. Getting 2200 lumens at about 18 inches for my phals and 4k lumens at about 6 inches from light for Cattleya. Flowers and works nicely. Heat a bit of a problem for me in Sept (growing in garage shed) but perfect temps in the winter. Shed about 55f and box stays about 80/60f on coldest winter days.

tropterrarium · #9 09-08-2011, 04:16 AM

Four issues have not been addressed yet:
1) Relationship of light out-put and distance of fixture to tank. If you want homogenous light from the top to the bottom of the tank, then the light source has to be further away from the tank. Remember inverse square law of light attenuation with distance. But, with greater distance you also lower overall intensity. This is a typical trade-off situation.
2) Color rendition index, i.e., how well does the artificial light match the natural sun-daylight. CRI of 100 is perfect match, regular cool white T12 is around CRI of 60, full spectrum HO fluorescent can be up to about CRI of 90, some MH are up to CRI94-96.
3) How much light do you need? Usually light requirements on culture sheets are for noon-midday, so peak intensity. But morning and evening light is lower. Artificial light is fully on or entirely off. Converting the natural light fluctuation to a square intensity function (i.e., squaring the "circle", though a parabola is the better approximation), roughly half of the culture-sheet requirement is about right for artificial light intensity.
4) What about LED's? they are up and coming in the coral reef community, and corals need A LOT of light.

I use on a 5'L x 2'H x 1'D 4x 80W 60" HO T5s. Seems to be enough, even with having all four on only for 3h a day. I do not grow very high light intensity plants (vandas etc.). If I would be in the market for a new light, I would very much look at LEDs. Don't know about their CRI.