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Making the switch on my highlands

  • Thread starter swords
  • Start date
I've decided to switch from using my power compact flourescents to metal halides on my highland enclosure but I know plants dislike a sharp increase in light all of a sudden.
How would be the best way for me to do this?

Here's the setup:
4 ft H x 4 ft W x 2ft D plastic and plywood enclosure (plants at different levels most neps about 24" from lid
humidistat keeping the air at 80%

I want to switch from 175 watts PC flourescents to either 175 watt or 250 watt metal halide - I have bulbs and ballasts for either - which would be better the better choice?

Thanks for any info!
 
Well I don't grow under MH lights so I can't say much about wattage and distance to the plants.

As far as acclimating them, seems like there are a few ways. You could place the light farther away and slowly move it closer. Or you could filter the light with something and take it away slowly or replace with progressively less opaque material (careful it's not flammable and too close to the lights). Or you can start with a short photo period for the metal halide while keeping the compact fluorescent and as you increase the halide timer do away with the fluorescents
Tony
 
Tony you have a greenhouse but you do use some form of supplemental lighting don't you? Many of the plants I got from you were very red (I love that) and they turned back to green (the new growth) now and I'd like to get them to put that red back on!
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Light levels in greenhouses are normally much higher than that what artificial lights do supply. Eyes do adapt very fast to differnt light levels and so you do have to take some light meter to compare it. If you have a photo you may use its meter to compare your old fluorescent lights with the metal halides. The spectral distribution will be different, but it will give you an idea of the difference in light levels. The efficiency of fluorescent and metal halide lamps should be quite similar, so to really get more light I would recommend the 250W system and for even more use a combination of both lamps... The 75W metal halide lamp I do use as additional light in winter does produce about 6-8 times less light in a distance of 60cm compared to a light cloudy sky in summer in my terrarium, sitting at an east facing window.

One of the big differences you will see immediately is that mh-lamps are point sources of light and doesn't produce the diffused light of fluorescent tubes. It is easier to reflect to your growing area but as a consequence you do get quite shaded areas under your plants. Building a phototron with reflective material does of course help to increase light levels and get more diffused light but it doesn't look to nice.

A word of caution: MH lamps do get very hot and be very carful not to place any plastic or other material which may burn next to them! Only do use glass as material between the lamp and your plants - this glass a few cm away from your lamp will get so hot, you can burn you fingers easily!

Joachim

P.S.: I have never seen plants grown under artificial lights which yield the same colour and grade of colouration like the Nepenthes Tony supplies (from what I have seen on pictures of his plants)...
 
I do use 2 tube fluorescent shoplights for the lab. My current Ghouse has no supplimental lighting though.
Tony
 
Thought I would add this here.
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Josh, when I recently had my gh modified by the electrician I had him put in 2 2 outlet receptacles over head on one of the wood stiffener beams and i am going to have some flurescents in different areas of the gh. Probably over the ones that like the light most like N.merrilliana, N.Gracilis "Nigrapurpurea", Heliamphora, and Drosera. But I am going to have 2 main fixtures over head that will cover a wide area in the winter and late winter.
 
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