Due to the facts that :
1) Leds keep evolving all the time...
2) Knowledge about growing with leds evolves along ...
3) There's not enough money around ,for building led DIY projects ,with high quality (and expensive ) parts and materials...
I'm going back to the cheap and 'comfy' asian 1-watters ....
Their relatively low-cost (note :
vastly differing quality between brands/manufacturers,for the same price !!! China-Way),along with their
easy soldering /mounting abilities ,allow the DIYer to use them in large numbers (pieces)...
Since they run @ ~ 350mA ,they are easy to keep cool ...
Since they are used in large numbers ,they offer the ability of evenly distributed light power ...
Their 120-130 ° emission angle ,is great for 'close encounters' with plant's canopy ...
They are easy to find/buy/replace ...
As for their efficiency ....
Well ,let's just say ,that it gets better and better ..
(Rather slower ,than the high -quality branded ones ,though...)
...I've used Astir panels before ,I know they do the job .....
(At least as good or even better than a 400 Watt HPS,for 144 pcs of 1-watters => ~ 130-140 Watts ,at plug ,with cheapo CC drivers included)
....
Now ....
I've read that guy's project a bit ....
(Not a mj grower ... )
http://www.sevengens.com/index.html
Some interesting parts :
LedEngin horti leds ...
http://www.sevengens.com/id98.html
His build :
http://www.sevengens.com/id97.html
http://www.sevengens.com/id90.html
http://www.sevengens.com/id113.html
http://www.sevengens.com/id85.html
And his
Wavelengths page...
http://www.sevengens.com/id75.html
And my notes about it (in red ... )
* 200-280nm or UVC radiation is harmful to plants.
^^^^^^^^This is the UVB range.Yes ,harmful if more than ~500mW / sp.m...
Otherwise,it promotes anti-oxidants biosynthesis ..And many more ..
(At least to plants that are exposed in UVb radiation when cultivated,to their natural habitats.
MJ is one of those ... )
.* 315 380nm is the UVA range.* 320-340nm MAY have effects on cryptochrome.*365nm a "wavelength of interest" .
* 410nm LED have no effect that we know of.
( I disagree with that ...At least regarding mj )
.* 439nm the blue absorption peak of chlorophyll A.* 450nm Royal Blue is a readily available LED wavelength, commonly used to excite the remote-phosphor in LED lamps and is absorbed by one of the peaks in beta-carotene 450nm .* 469nm the blue absorption peak of chlorophyll B.> Chlorophyl both a and b have very wide absorption in the blue, between 430nm and 470nm is pretty much equally effective. You'll need a lot of this.
.
No, you need less than 15-20% of total power ,and thats while vegging .In flowering even less ...Regarding mj ...
*480-485nm second absorption peak of beta-carotene
.
* 525nm this is a phototropic activator our researchers are still trying to find the chromophore of.... It is apparent the plants are gaining direction and environmental signals from it... it effects internodal distancing in ways which most folks may find confusing! 525nm is also the wavelength of GaN or InGaN green LEDs commonly used in RGB displays, or mixed with red and blue to get white light.
* 590nm Carotenoid Absorption... carotenoids are both starch storing, structural compounds and nutritional compounds.
Jeffery Bucove increased the harvest bulk of his plants some 3 time by adding this wavelength.
Smells like HPS ,here ...
.
* 590nm phycoerythrin single absorption wavelength
.
* 625nm phycocyanin single absorption peak
(Does he grow sea-weeds ??? !!!! )
.
* 642-645nm is the peak absorption point of Chlorophyl-B.* 660nm Super-red LED wavelength --readily available sub for 670nm, multiple manufacturers, 1, 3 and 10W .
* 666-667nm this is actually the peak red absorption point for Chlorophyl-A
Actually is 662 nm when in solution ....
.
* 700nm light is to be avoided. It confuses the Phytochrome recycling systems in green plants
??? How,I wonder ,really ?
Emerson effect ,says opposite ,nevertheless...
.* 730nm for phytochrome recycling: needed for all kinds of morphogenic processes. A few minutes of 730nm light treatment after the full light cycle is over will revert the Pfr (activated) to the Pr (inactive) form of the phytochrome chromophore. This resets the chemistry for another lights-on cycle, and MAY be useful in shortening the classic dark side of the photo-period, fooling flowers and fruit into feeling a 24 hour day even though they got less hours of darkness than they 'think' they did...
.
And can induce all sorts of stretching effects,also ...
* 735nm is the closest available standard LED wavelength to the above 730nm
So .....
My next six ( ~130 Watts altogether) Astir panels ,are going to be (something )like that ....
10x 640-650 nm Reds : Main PS engine for both A & B photosystems (Perfect for neither of them ,but good enough for both ..) .
8x WW 3000K 80CRI : For activation of (crucial ) photo-protective accessory pigments .( Yellow-Amber-lower red wls )
4x NW 5000K 75 CRI : Green wls needed ...
1x Blue 460-470 nm : Main engine for blue wls ..(Stomata have to stay open ,you see ...)
1x Violet 400-410 nm : Some anti-oxidant biosynthesis ' light push ' ..For extra quality ....