Clamp-on CFL Grow Light 2700K/40W....
 

I just ordered a Clamp-on CFL Grow Light - 2700K/40W bulb and fixture to supplement my windowsill growing.

Does anyone know how effective these Lighting fixtures and bulbs are for orchid growing??

Thanks

Unfortunately, not very...

The initial output will be on the order of 3600 lumens, but you'll have to have a reflector that focuses it onto a fairly small area at close range for it to be strong enough.

Secondly, a 2700K bulb has almost no light output in the blue end of the spectrum,which is critical for blooming.

Re: CFL Grow Lights ....
 

Ok, Ray, well now you have me totally confused, because the website advertised this bulb and fixture as being in the RED area which IS FOR BLOOMING FLOWERS. It stated the BLUE area is for overall growth.

Can you now clarify for me......?

Thank you in advance.

I now grow exclusively under lights and have immense success using 28W 6500K (Daylight) CFLs, I believe they are called Reveal and have a 1750 lumen output at 12". Depending on the light requirements for the orchids, the lights are between 4"-18" away. I use the daylight spectrum bulbs since they are the closest to natural sunlight available. They grow with sun in nature, so why not use an artificial spectrum as close as possible to grow indoors? :)

I currently have Dens, Neos, Catts, Phals, Oncs, Paphs, and Brassia - hybrids and species - blooming with this setup.

In all honesty, it seems that if you think the lights are too close, they probably aren't! Most every one of my plants is receiving more than the "recommended" amount of light and they are growing and blooming like mad!

Re: Clamp-on CFL Grow Light
 

Thanks so much for your reply. Very helpful.

The bulb and fixture I ordered are 2700k/40W, giving 2650 lumens.

I am using it in my small windowsill area where I grow Neofinitia falcata's potted on the windowsill and grow Aerangis/Angraecum's mounted on the inside windowsill wall....most of these are Low/Med. Light orchids. The natural light exposure is SOUTHEAST, so these orchids all get very Bright early Morning Sun from 8AM to 11AM.

Any thoughts ....?

No problem!

I can give you my setup and you can judge from there. This is what has been working for me!

I currently have my Neos (crosses and Falcatas) 8" under my 28W bulbs. All 6 are currently in spike or flower.

They are situated in an east window that is shaded by trees about 20' away and receive dappled light from 8-11:30AM. My lights are on a timer starting at 6AM and shutting off at 8PM. Without these lights, the natural sun that comes through wasn't enough to create active growth in my Phals. There are also a few Catts with the Neos and they have been blooming reliably on every growth since I added them to the area.

When I spoke with my local grower he told me a way to estimate the light they are receiving by taking the lumen output and dividing it by the distance from the bulbs, squared. For example, my Neos are 8" or 0.66 feet from the bulb. The lumen output at 12" of each bulb is 1750.

1750/0.66² = 4,017

Lumens are not equal to footcandles, but I make sure that the lumen number is over the recommended footcandle light requirement by between 300-500 and that seems to work out magnificently for me. :-) Who knows if this is the correct way to determine the distance, but I'm too cheap to buy a light meter and instead go by my results. :biggrin:

If yours are receiving bright light for an extended period of time, I wouldn't place the lights as close as I do. Begin high and lower them over time until you see your plants reacting to the light. My Neos are healthy green with very little red blushing/spotting.

Re: Clamp-on CFL Grow Light ...
 

Great. Thanks. Big help.

I tried to find information on the Bulbs you use --- the 28W 6500K Daylight Reveal bulbs. I couldn't find any information on them at all and found no one who sells them ....................can you help me with this ?

Yes, I get alot of bright morning Sun in my SOUTHEAST window where all of the Neo's are, and the mounted Aerangis/Angraecums, but I still don't feel the light is so bright that it is beneficial, so I'm adding the Clamp-on light...... I always feel orchids do better with More light than with Less light ..........

Thanks again......

Let me know about your bulbs.

I buy mine at Target or Home Depot, they seem to always have them on hand. Online, I can only find the 26W version at 1570 lumens, which would work just as well but would need to be closer to the plants (obviously):

Amazon.com: GE 75408 26-Watt CFL Spiral Reveal Light Bulb, 100-Watt Equivalent: Home Improvement

I can't estimate for you how high to start with the supplemental lights, but if you feel they are receiving a good amount of natural light and just need a boost, I would work out your distance so that lumen output reaching them is around 1500-2000 and see how they do.

I don't think that they're the most practical thing to set up in a windowsill, it's far easier to hang a cfl fixture IMO.

Which LEDs are you referring to? Most inexpensive LED panels on the market (under $50) are very low in light output and come in at around 400 lumens or less. These would need to be within inches of the plants in order to deliver the amounts of light received by a single 26W CFL at a foot or more. Quad band panels are just now hitting the market and aren't all reasonably priced and still need supplemental full spectrum CFLs in order to induce successful flowering (plus the red/blue LED combination is not all attractive if the setup is in your home and not a designated growing area or room).

The last I saw of LED light bulbs they were not much better in output - are there new ones you are referring to that I haven't yet seen? I'd love to know! :)