Distance from 4' T5HO

[orion141]

Hi all!

I just set up my Hydrofarm FLP44 fixture (4 foot x 4 bulb T5HO with 6500 bulbs) on one of the Lowes wire racks with adjustable shelves. I have 2 phals, 2 oncs, 1 paph, and 5 cattleyas. I was wondering if anyone has experience in terms of how close to the lights to put these different species with this fixture (or a similar fixture). I have seen numbers all over the place with different fixtures so I figured I would just ask.

Thanks!!

[jeremyinsf]

I have some of these and I love them. I had to take two of the bulbs out in some cases because it was too much light.

I'd start with your plants at 18"-24" away from the bulbs, and adjust it from there.

Remember too - how LONG the lights are on makes a big difference as well, in terms of how much light they are getting. Important to take that into account from the start.

[orion141]

Originally Posted by jeremyinsf

I have some of these and I love them. I had to take two of the bulbs out in some cases because it was too much light.

I'd start with your plants at 18"-24" away from the bulbs, and adjust it from there.

Remember too - how LONG the lights are on makes a big difference as well, in terms of how much light they are getting. Important to take that into account from the start.

Thanks for the response! What kind of orchids did you find were having a hard time with the amount of light? Right now I am giving approximately 12 hours of light to them.

[zxyqu]

Well the catts and the onc will need more light than the Phals. I'd say 24 inches is a good starting point, but I'd prop up the high light plants on an inverted pot or something so they get a bit more. Remember start with less and lower the lights slowly. I leave my lights on for 14-16 hrs.

[jeremyinsf]

I grow mostly paphs. Some closer to the lights, but I agree with others that it is better to start farther away (that's why I said 24" to start with) and then move closer.

These bulbs are pretty powerful and put out of a lot light!

I'm down to 9hrs right now with my setup.

[ronaldhanko]

I have a wardian case or orchidarium with and 8 bulb fixture (T5 HO). Plants such as Pleurothallids are 30-42 inches from the bulbs and higher light plants, such as Dendrobiums range from 24 to a few inches away. You can see the plants here:
Orchids in Bloom: Rebuilt Orchidarium

Originally the growing area was 12 inches shorter and I had to shut off four of the bulbs since some of the plants were getting "sunburned" from too much light. My lights are on from 12 hours to 15 hours - longer in the winter and shorter in the summer - I change the timer one way or the other every month.

[trdyl]

I have my most of my Cattleyas 2 to 5 inches below a 6 bulb fixture.

[jeremyinsf]

I should add that I do have Paph druryi about 4" away from bulbs too. All depends on the plants!

[orion141]

Thanks for the help! Everything now is about 18-20 inches from the light as of now (except for a couple of the taller cattleyas which have the tips of a few of their leaves about 10-12 inches away), with my phals and paph on the outside of the shelf so they should receive less light also. These plants have been under the lights for about a week now. How often and by how much would you decrease the distance to the light?

[jeremyinsf]

Id leave them for several days the way they are. Perhaps, a week. Then start moving them closer. You don't want to do it too fast, because it will take some time to notice how they are reacting (unless you outright burn them). Maybe a couple inches a week at most.