calculating growing space with metal halides

[swords]

I have several different currently unused metal halide ballasts
175 Watt
250 Watt
dual 400 Watt (runs two independent 400W MH bulbs) can be used over one enclosure or over two seperate enclosures-depending how I mount the sockets.

Each bulb I have is 5500K or 6500K color temp.

Is there a way to calculate how much growing space each bulb will give me and how high should the bulbs be hung above the plants? 3 - 6 feet? I know the intense heat will cause dryness of the air but a humidifyer and fan should take care of it.

Thanks for your thoughts!

 

[neps]

Couple of remarks:

First, be really careful if you have the light(s) and/or ballast in the same area as the plants
themselves. Obviously, you don't need me to point out to you the manifest problems which
arise upon the mixing of water and electricity! However, in addition to this clear hazard, it
is also the case that humidity will rust the light fixture, and could even result in the bursting
of your bulb!

Secondly, and to address your question directly, I know that you can illuminate an area of
about 1.8 m by 2.4 m quite well with a 1000 W HID lamp at about 1 m, and secondary
illumination (enough for a lot of low-light plants) is about 2.5 m by 2.5 m. You may have
to experiment a bit to determine the limits of your particular equipment, or consult a
specialist at a hydroponics store. FWIW, however, you can probably figure it out to your
satisfaction by just running the equipment and "eyeballing" it to deduce the area reasonably
well illuminated. And, if you are burining your plants, you may be able to use shade cloth
to reduce the intensity of the light, provided, of course, that you don't have the shade cloth
in such proximity to the light to raise the possibility of its ignition!!

In any case, good luck! I think you will find that this is a good way to grow these plants.
I use such equipment for my highland Nepenthes and it has served me well for years.

 

[Joachim]

I would go for the 5500k bulb which does produce more natural light than the 6500k bulb, but the difference won't be much. I'm using a 70W/4200k metal halide lamp for a 120cm x 60cm terrarium (mostly highland Nepenthes). Light levels are much higher than before with 80W fluorescent growth lights which were also sufficient - but I do have to mention that my plants get high natural light levels at daytime and additional light is only really needed when the days get shorter in winter.

Joachim

 

[mato]

Sooo, did you ever come to a decision on this, Josh?