fluorescent grow lights

[Chris35rt]

Good information for a beginner like me but after reading this seems my 4 T12's might not be enough for my Cat's

[clusty]

Hey,

So I got myself 2 sunblaster 3' bulbs 6400k rated at 3600 lumens. I added a reflector that looks to be around 120 deg.

Using my SLR I tried getting an estimate of the light intensity and got something like 8000fc (ISO 100 f/8 1/2000).

Does this make sense??????
If these numbers are right, 1 should be enough for cattleyas.

Light Intensity Measurement

[rick84]

clusty,
I would say that you are safe with the two 3600 for sure. If you figure~ 8000 lumens, I would say that's a good estimation considering now your using reflectors. This is said to increase not the total lumen count, but the ability to focus/direct a footprint and maintain plant canopy penetration.

---------- Post added at 06:20 AM ---------- Previous post was at 06:12 AM ----------

Originally Posted by Chris35rt

Good information for a beginner like me but after reading this seems my 4 T12's might not be enough for my Cat's

if you have t-12 they could be enough for vegatitive growth depending on the wattage. The cat will need more wattage to flower and in a dominant red/orange hue. HPS or 2700k/2800k or, a dual spectrum cfl to maintain an even balance of reds and blues. MOST orchids are photoperiodic and take their cue to flower based on the total hrs of light received and dominant wavelength. Blue to grow and red to flower. With a dual spectrum bulb all you do is switch the hrs from 16 down to 12 for flowers. And a temp drop of 10-15.

[clusty]

When I measured before I shone the light straight at my SLR.

If I put a white paper on top of the plants and measure, I get around 1000FC

[naoki]

Originally Posted by rick84

if you have t-12 they could be enough for vegatitive growth depending on the wattage. The cat will need more wattage to flower and in a dominant red/orange hue. HPS or 2700k/2800k or, a dual spectrum cfl to maintain an even balance of reds and blues. MOST orchids are photoperiodic and take their cue to flower based on the total hrs of light received and dominant wavelength. Blue to grow and red to flower. With a dual spectrum bulb all you do is switch the hrs from 16 down to 12 for flowers. And a temp drop of 10-15.

Chris, generally, people say that Catt needs lots of light to flower, but some of them can flower with less. Long time ago, when I was a high school kid, one of my standard Cattleya hybrid flowered regularly under 2x 40W T12. You have to place the leaves almost touching to the bulbs (about a couple inches, without overheating the leaves). So it may work. However, if your fixture can handle T8, you should change the bulbs to 32W T8. You get more light with lower energy consumption than T12. But if you can afford T5 HO, you can provide more light for a given area.

Rick, are MOST orchids really photoperiodic? I wouldn't expect that from plants coming from near equator. Also, with Cattleya, there are quite a bit of different growth pattern among different species. So reducing the temp and lower day length may not be the flowering cue for all species.

---------- Post added at 10:51 AM ---------- Previous post was at 10:38 AM ----------

OK, I was curious about photoperiodicity, so a quick google search to answer my question:

http://www.cvios.com/Doctor%20Archiv...and%20temp.pdf

Bottom of p.3, it says most of hybrids are speculated to be day neutral even though it is not tested. Some species appear to be facultatively photoperiodic (i.e. night length is not absolutely required to induce flowering). Some Cattleya (C. labiata, C. mossiae, C. trianaei etc.) are short day, and others (C. dowiana, C. intermedia) are long day plants.

[clusty]

I read somewhere that after 6 months the t5ho tubes lose vigour (spectrum shift/dimmer light). I was curious how bad is this phenomenon.

[naoki]

Originally Posted by clusty

I read somewhere that after 6 months the t5ho tubes lose vigour (spectrum shift/dimmer light). I was curious how bad is this phenomenon.

I'm sure some color shift will occur in any fluorescent light due to phosphor degradation, but I'm not sure how relevant to the plant. According to the last page of:
http://www.xrite.com/Documents/Liter...aylight_EN.pdf
The color shift of 400K could occur (to higher temp due to red light decreasing).

For the lumen maintenance curve:
T5 Benefits | Solar Energy USA Commercial Lighting

I don't know if the figure is really true without marketing BS, but I'm surprised how long T5 can maintain the lumen. The figure is for normal T5 (not T5 HO, which is more frequently used in orchid growing), so T5 HO may decay faster. Also lumen maintenance depends on how the bulbs are used, too (i.e. types of ballast and how frequently turned on and off).

[DavidCampen]

Originally Posted by clusty

Guys from Build My LED Custom LED Lights for DIY Horticulture Aquarium Hobby Lighting , look like the real deal. However 200$ is a bit steep

It is $270 for a 60 watt fixture that delivers 90 micromoles per second. That is $5/watt which is the current price for a horticultural LED fixture. If you see fixtures for sale claiming a significantly lower price per watt they will be cheaply made junk and untrue wattage claims.
All Purpose Red Growth Spectrum - Build My LED, LLC

[clusty]

My new rig is almost ready.
I currently grow phals catts, oncidiums and 2 dendrobiums.

For now they are configured to run for 12h. I was wondering if plants are majorly photoperiodic to induce blooming. I read somewhere that current catts have had their photoperiodicity bred out of them.