a step beyond T5's .....I found T4's

[Ray]

I have been participating in a Linked-In discussion about LED lighting, and my stance is that picking a few, discrete wavelengths - even if they are dead-on the "peaks" in chlorophyll absorption - is passing up on absorption and energy conversion over the rest of the curves, which to me seems to be "wasted opportunity", and might even lead to deficiencies in plant growth.

Look at the attached image, which shows the absorption spectra of chlorophylls A & B, plus beta-carotene, which absorbs the light and passes on the energy to the chlorophylls so they can work more efficiently.

The uptake by the plant is the entire area under the curves, so how can irradiating a few, specific wavelengths be efficient?

[Ray]

Stephano - I think you are getting some incorrect information about the 6500°K bulbs not being particularly good for growing plants.

At roughly that color temperature (correctly-called corrected color temp in fluorescents and LEDs, as they are not black body radiators) the heights of the blue peak and the red peak are in approximately the same ratio as the absorption of the chlorophylls, and because physics mandates it, at higher color temperatures, it take more input energy to excite the electrons sufficiently to produce such a spectrum, so you actually get more red out of a 6500° bulb than you do out of a lower-color-temperature, warmer-looking bulb.

[calbunn]

Originally Posted by Ray

I have been participating in a Linked-In discussion about LED lighting, and my stance is that picking a few, discrete wavelengths - even if they are dead-on the "peaks" in chlorophyll absorption - is passing up on absorption and energy conversion over the rest of the curves, which to me seems to be "wasted opportunity", and might even lead to deficiencies in plant growth.

Look at the attached image, which shows the absorption spectra of chlorophylls A & B, plus beta-carotene, which absorbs the light and passes on the energy to the chlorophylls so they can work more efficiently.

The uptake by the plant is the entire area under the curves, so how can irradiating a few, specific wavelengths be efficient?

I happened upon the spectral distribution graphs of wide spectrum phosphor blends and it would seem that the 6500K color corrected lamps emit less red then phosphors that luminesce in the 620-655nm wavelengths.

Has anyone on these forums had any experience with these lamps and if so were they for vegetative, flowering or both with, as advertised, a single lamp?

Inda-GRO

From this link keep advancing on the next key to see the SDG charts for the 6500K and various other lamp types.
Interesting galleries too.

[johnblagg]

LOL you are realy into the high tech expensive stuff ....Having never saw one of these in real life I have no clue ...heard the promises about them for years and how cheap they would run ect but never saw one in production....
As for spectrum ...lol relax your trying way to hard to make this rocket science instead of fun.I would bet I can take a off the shelf 6500k light of high wattage and grow almost anything I want unless we are talking Cactus then blooming is not a issue either ...cactus can be tricky and need realy intense light to bloom some types so they might require hid lighting because of the lumens needed to simulate high desert

[keithrs]

Originally Posted by Merlyn

Dimming as an eco friendly or financial savings option is an oxymoron created by greedy marketing !!! A dimmer is NOT like a water faucet where you turn the handle and the water flow slows down. When you turn the handle on a dimmer and it dims your 100 watt light to 50, you put the other 50 watts on your dimmer and it comes out as heat !!! No matter what THEY say, you keep it dimmed to 50 watts for an hour and you WILL get charged for a 100 watt hour !!!! You CAN'T reduce the 110 volts with a dimmer !! If you know OHM's law E=I x R and P=I x E you know what I mean. There is NO SAVINGS, except for light bulb life, when using a dimmer !!!! The rest is simply marketing BULLS**T masquerading as eco-friendly !!!! The same BS also applies to the CFL bulbs being eco-friendly when they contain mercury just like all the other florescent tube types do !!!

Your right.... Voltage will always stay the same..... but amperage will change. I think Watts law is better suited for lighting if you know what E and I equals. When you dim the lights, the Intensity(amperage) will change, there for both in & out wattage will change. Digital ballast can change wattage and reduce the about of energy used without creating tons of heat.

I sure hope no ones has digital TV if using a high freq. digital ballast. Talk about crappy picture....

[johnblagg]

yep digital ballast run at high enough froquency to emit radio
static

[Vanda lover]

I have a single Sunblaster t5 type light that my brother bought for me at Lee Valley tools.It is designed so that you can plug a second one in to it. It was around $30 and I'm amazed at how well it is working. My studio looks like it is sunny all day now.

[silken]

Originally Posted by Vanda lover

I have a single Sunblaster t5 type light that my brother bought for me at Lee Valley tools.It is designed so that you can plug a second one in to it. It was around $30 and I'm amazed at how well it is working. My studio looks like it is sunny all day now.

Those Sunblaster T5's are just about all I use now. I do wish their connecting cord to mult them together was a bit longer in some cases. But for the most part it is long enough.

[Vanda lover]

I really like them. I'm going to get another one.

[stefpix]

Was it $30 for the bulb/tube only or the fixture? What specs? Thanks