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

[johnblagg]

Stefpix as for leds ... I have far to much area to cover and I actually found a good comparison recently of induction fluorescent, leds, and hid lights .. leds took the lead in most areas except for the fact they have to be very very close to the plants .
And the company that did the research was the induction fluorescent light maker so Im pretty confident in the results ...lol they would not post results that show leds are better if they were not
....leds placed close even beat hps and mh hid lights

[stefpix]

I am just saying LEDs panels are great for a shelf with plants that are not too tall. leds are 5 to 10 inches from plants. a few grew so fast that the leaves were touching the LEDs after 2 / 3 weeks.
I also got a 90 W UFO hanging on my window, it is a lot brighter and more red I think it does not to need that close, , it can cover easily a square with a side of 3 to 5 ft. LEDs replaced 40W CFLs ($7 at adorama.com for photo / video light fixtures.) that made my bedroom look too bad. LEDs do not look so brigt to your eye unless you look straight into them, but they seem bright enough for plants.

[Magnus A]

Originally Posted by johnblagg

there is no reason you could not use this with a reflector it is flat and just 4 x 8 .... and lol they hang just a few inches below a shelf painted flat white one of the best reflectors you can have in fact ... as for lost light there is no such thing with every surface painted flat white when I use every bit of it for growing something and have enough light to grow pepper plants in the center and I have a 10 x 20 room so how is it lost ?The only light that is lost is what spills out the windows .... as for measuring light since I bloom everything from catts to den aggregateum under them and at anything closer than 1 foot away from the lights get reddening of leaves and minor burn I see no need to measure ... the orchids approve and thats all I need

The problem with a reflextor on this one, is that the tube itself will shadow the reflected light. And the reflected light from a white roof is in prinicip none! A "silver" lined designed reflector for a single T5 straigh tube "bend" the reflected light around the tube and you acctually increase the light hitting the plant with almost 100%!

Reflection in a white sealing is NOT good and as the light intensity falls with the distance squared your roof is not giving you any usefull reflection at all! Do not fool yourself by your eye responce. They are useless to measure light intensity as they are VERY good to adopt to different light levels...

/M

[johnblagg]

Stefpix I was saying they seem to be great for growing the only problem for "ME" is that they have to be to close

[stefpix]

Johnblagg, They have to be close but not too close. I think a 135W UFO LED can be not close as it has 3W individual LEDs that have more depth. But 14W panels with 225 LEDS are great for smaller orchids on a shelf or in a vivarium

[johnblagg]

Originally Posted by Magnus A

The problem with a reflextor on this one, is that the tube itself will shadow the reflected light. And the reflected light from a white roof is in prinicip none! A "silver" lined designed reflector for a single T5 straigh tube "bend" the reflected light around the tube and you acctually increase the light hitting the plant with almost 100%!

Reflection in a white sealing is NOT good and as the light intensity falls with the distance squared your roof is not giving you any usefull reflection at all! Do not fool yourself by your eye responce. They are useless to measure light intensity as they are VERY good to adopt to different light levels...

/M

lol you need to do a bit of research flat white surfaces do a much better job that silver reflectors and in fact I am using a surface not 5 inches away above the lights in most areas painted flat white for this .... and as for the bulb blocking light your "silver" reflector actually blocks as much or more because it is highly polished and reflects directly back at the bulb in fact ....

here do a little reading before you argue about things you dont seem to know
Simply Hydroponics - Evolution of Reflectors

After years of research and testing, a flat white surface - coated with Titanium Oxide - gave the highest light levels, with the most even light distribution. It reflected 20 % more light than the best glossy white finish, without the uneven glare that's characteristic of high gloss surfaces. In fact, a unique method of applying the Titanium coating worked so well, it directed up to 95% of the light hitting the reflector down to the crop. Add this reflected light to the direct light from the bottom side of the lamp, and lighting efficiency in the garden became nearly perfect!

and in a different field of application ... Which by the way I also have experience in ......
http://www.usc.edu/CSSF/History/2010/Projects/J1005.pdf


The total reflectivity of a good white paint nearly equals that of
silver, and is certainly better than any aluminized surface (mylar,
foil or sheet metal). The difference between a diffuse (flat white or
brushed metal) reflector and a specular (polished metal or mirror)
reflector is the direction of the reflected light.

[silken]

I don't know any of the scientific stuff behind it but some of my T5's have big white reflectors and you can definitely see the difference in light being reflected down on the plant than a few of the same lights that I have yet to make reflectors for. I've used them for a few years and stuff seems to grow well.

[johnblagg]

Originally Posted by silken

I don't know any of the scientific stuff behind it but some of my T5's have big white reflectors and you can definitely see the difference in light being reflected down on the plant than a few of the same lights that I have yet to make reflectors for. I've used them for a few years and stuff seems to grow well.

LOl I am not arguing that reflectors do not help ... and I do have a surface behind the lights painted flat white just for this ... not high tech but above and on one side both so light is being reflected. I am simply saying flat white surfaces are in fact excellent and often better than highly polished silver reflectors.

No matter what kind of reflector you have some light is going to be blocked by the light itself and its impossible to eliminate that totally ... but since I get 65 watts from a light 4 inches wide by 8 inches long and do have a flat white surface a few inches above and behind them I am not wasting any light and in fact the light from the upper surface of the light is redirected back into the room evenly and is strong enough to actually grow full sun plants anywhere in the room I want to place them .

I am arguing the statement that flat white paint is not close to if not better than a silver reflector and if you look you will find that many hid and fluorescent lights do use flat white reflectors instead of silvered ones ... the Shape of the reflectors do make a huge difference of course but in many cases flat white is better than highly reflective polished reflectors simply because they reflect in all direction not at right angles like a mirror does giving you more light actually striking the leaf surface evenly resulting in better adsorption by the plant and used ... focus all the light In a small area on one leaf or over the entire plant ....hmmmm which will grow better

[silken]

I'm just saying that I agree with you on white being a good reflector! That's all. Even white t-shirts reflect sun and heat better than other colours. And a whit flower in the garden at night or on a dull day glows as it reflects light that other colours are absorbing....