Underlights...be still my beating heart

[Phaeton]

Not the most thrilling subject. Do not see a lot of threads floating around about the bottom of the bottom leaves.

Autistic, the stereotype for being perfectionist, I will not say anal retentive, anyhow, my lights are dialed in pretty well. It took 5 grows of paying serious attention, but the forum being a cross section of humanity I am sure I have company in here.

I will skip the cooked stems, wilted leaves, shorted CFL's and all the things I learned that did not work.

The LED T8 replacement tubes I use in my SAD (seasonal affective disorder) room gave me an eureka moment. They are 140 degree 22 watt 5000K LED's 4' long. Bright, squinty to look at them lights. 110v either end lights them up.

I grow trays, row of 4, row of 3, row of 4. 11 plants. The canopy is 3' x 4' and the LED's fit right down the rows and just one socket with 110v slips onto the end of each.

Enough light is emitted to make the innermost leaves glow from transmitted light. And the glow is yellowish, the blue is getting sucked out by chlorophyll. No bleaching in 5 days, heat is spread over the entire 4', no hot spots either.

As noted, I am not the only perfectionist, other members, anguished (those leaves are not getting consistanly equal light), are possibly trying underlights in DIY (not much out there) mode. The rate of improvement from top and sidelight manipulation having reached the point of tiny returns for the effort, leaving underlights as the next area for visible gain.

What has been done underneath that has not caused damage?
Any discrete colors been tried?

See, I'm not after much. But at the cost of LED light, I really really really do not wish to duplicate layouts proven not to help (violet light) or even cause active damage (T1 CFL's) when each light costs multiple hundreds of dollars.

Time is not of the essence, the white LED's under the indica will keep me occupied.
:kitty:

 

[Voidling]

I'd like more info on the light you are using and how it's going

 

[Phaeton]

Spectrum makes a difference.
I used 42 watts of CFL at 2700K. This balanced the red and far red level under the canopy, fooling the plant into thinking it was alone and didn't have to stretch. Plants that grew to 36" stopped at 30". It worked on the plants close to the light and curled leaves above it from the heat column.

I did not understanding this 'balance' and used research spurr had done indicating blue would be more efficient for the plant under the canopy.
The 5000K white LED tubes are 44 watts and no heat column. Full spectrum weighted on the green and blue.
This blue and green are the same spectrums plants reflect off their leaves. This fooled the plant into thinking it was surrounded and it panicked into a full out race for the sun. Stretch was almost double what it was without them.

Red LED tubes should work, but I have not seen any for sale.

Looks good but did not work.

 

[Voidling]

Good to know. Thanks. How many Watts would the red led tube need to be?

 

[Phaeton]

There were 11 plants in the trays I tested, the pair of 42 watt CFL's are about the correct intensity, but were too hot for undercanopy use.

The LED tubes are 22 watts each and rated at 5000k, but being residential lights they are heavy in green. 1900 lumen each with a 140 degree lens, twice as much light per watt hitting leaf surfaces as equal wattage CFL at 8". Heat is spread over the whole 48" and is not a problem, big point for LED's.
4 watts per plant was my average, and with 2 tubes inside 3 rows the coverage was pretty even for those 4 watts.

But back to the question, the tube is 120 x .183 watts. If red LED's could replace the white the wattage should be about half that.
The red should be 660 nm+ rather than -630 nm but 600-700 should work.
Within the limits results are a straight graph, more red underneath = slower stretch. The limit is how much red is hitting the top. Plants figure light ratios as if they had calculators.

In the science forum the 'DLI' thread by delta9nxs is full of much more detail than I remember for the theory. spurr also had a related thread, but I will have to go look for the title.

 

[Voidling]

Thanks for the info. I'll try digging up those threads later.

I'm thinking of scrogging so wonder if it'd help

Red tubes like these?
http://www.ledlightbulb.net/store/index.php?main_page=product_info&cPath=106&products_id=841

 

[Phaeton]

Red tubes like those? Yes, just like those, and they cost less than the white ones I have.

Bookmarked in my growlight folder, a pair of those is my next purchase, I thank you very much.

 

[Voidling]

You're welcome. There may be others, I have no experience with that company. I did a search term "660nm led fluorescent light replacement " or something to that effect.

My current setup is for running pl-l lights. Hopefully you'll have figured out underlighting by the time I replace top lights with led.