VerdantGreen's 104 watt micro grow with custom HG LED (ScrOG)

[VerdantGreen]

knna, thanks for checking out the grow, i think white rather than green is one of the specs that are being tested for these third generation units. interestingly i have one of the first gen units from hydrogrow that have white in the spectrum (but not the same overall ratios as this one as the third gen units are balanced using a quantum sensor type thing). my first impression is that the green may reduce the stretch a little over just white - but it will take a few rounds with other cuts of mine to see if that is correct. i hope you keep half an eye on my diaries as your feedback is really helpful to me and im sure others will like to read it too.

bootz - higher ceiling is the one thing i cant provide but yeah hopefully i can pull this off. i topped them all today and will try to root the cuttins under a very reduced light cycle to see if they will show sex for me. perhaps 10/14 will work. it would be very handy to know which are girls early on.

cheers

VG

 

[knna]

Yep, probably the far red that white LEDs emits makes some difference about stretch vs green LED which only emits green and no other wavebands. If researching, makes sense to use pure color LEDs in order to disentangle effects of different wavebands and no matter how many watts you use, but if yield is the expected. But when trying to save watts, using the most efficient solucions makes a large difference.

But anyway with both options stretching is already way smaller than with any standard light source. LED lamps are producing very little stretching, and difference between almost no stretching and slight stretch is usually difficult to notice.

My last research is focused on finding the right percentage of green-yellow to use for growing (no matter the exact LEDs used to get it) and likely is not an unique optimal ratio, but it varies with the irradiance used. The largest buds you want to yield, the higher irradiance you need to use, with a larger percentage of green in it.

So a spectrum that for a lamp of given watts works perfect on a 3 sq ft cab may not work as well on a 5-6 sq ft one (and Im not refering to not enough watts, but the relation watts/sq ft with the spectrum used)

 

[VerdantGreen]

that sounds really interesting kanna - about your research. from the little i know, green light needs bright 'white' light (as in light made up of different colours) in order to work well. the idea of finding exactly how much green for various intensities is cool.
i think this one has about 10-15%

as for stretch the way i grow tends to encourage a lot of stretch which is useful for a scrogger up to a point - i do quite a big repot at the same time as i got to flower and fit the screen. so the extra rootspace really promotes stretch. with the green i didnt get such big internodal distance though that i seemed to get under other lights, but as i say its way too early to be sure about that

atm this lamp is giving about 60w/square foot which is a LOT for LED. after this grow i will fit it in its correct cab which will give about 41w/square foot. im hoping to still get good bud development under it.

VG

 

[knna]

Green light works very bad alone, but plants do better when you add some green to a blue/red dominant spectrum. At low irradiances, as we generally are using with LEDs, a little green-yellow, about 10-15% of total works perfect.

But green light has an advantage over the normally higher photosynthetic efficacy red wavelenghts (and at way lower degree, blue), and its leaves get saturated of green at very higher irradiances than red and blue. So past a irradiance level, aditional red and blue light is used very bad (it could be said its wasted) while green is used near the same. Comparatively, its worse at low irradiances, but goes equalling red/blue as irradiance increases and at high irradiances, the average efficacy of green photons may be higher than that of red/blue.

Probably that explain why HIDs, that generally emits a lot on the green-yellow part, works so well at high irradiances (but bad at low ones) and LEDs achieve good results still at low light levels. In general we are using average irradiances in our LED grows about half of those used when using HIDs and getting yields similar or just slightly inferior.

But if a LED grower want to get the maximun yield from a given space (and not so much getting a good g/W figure), it makes lots of sense to use way more green-yellow light.

 

[knna]

This is the typical spectral distribution of a neutral white (~4500K) LED (the exact model is Lumileds Rebel).

The Y axis (vertical) represent the amount of light (typically measured on optical mW) emited at each wavelenght (color), on the X axis (horizontal).

Notice how it emits a strong but narrow peak on the blue range about 450nm and another one not so intense but much wider on the green/yellow (530-590nm) range, peaking at 560nm aprox,in the green close to yellow.

In these color tone LEDs, usually about 30-40% of the total energy is emitted on the blue (in wide sense, 400-500nm) while 40-50% is emitted on the green yellow (again wide sense, 500-600nm). Notice total energy emited correspond to the area below the curve. Rest of energy in on the red.

White is always the result on emission of different colors at a time. Thus white LEDs are a good way of getting a background with all colors, then adjusted by using pure color LEDs.

 

[VerdantGreen]

cool chart knna. do you know the total energy of the green ones? pretty sure my ones are 525nm
when i was looking into coloured t5's for supplemental lighting i found that the green ones emitted a lot of light compared to other colours - but i guess that was measured in lumens so that could skew the figures a little...

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well the plant is in there still! 11 weeks and it's getting ugly i will chop it tomorrow if i have time. smells fantastic - of parsnips

VG

 

[fat-rob]

fucking fantastic, im extremely interested in these led's now and i cannot wait for harvest pics and final bud shots. K+

 

[knna]

Yep, they are becoming very fat and ugly, no doubt

Human perception of light (measured in lm) is very selective. Sensation of green light is about 10x higher than that of blue and red, thus lm or our personal sensation is very misleading, as plants use the energy (actually, the photons that carry it), and a green light and a red light with same energy may have a difference over 10 fold in lm.

When compared to a white source (a LED one, for example), difference is not so huge, but still is very noticiable. White LEDs produces (depending on actual color tone) 270-340lm for each optical watt (emitted light) (this is called LER, Luminous Efficacy of Radiation). While green LEDs produces over 500lm for optical watt. It depends too of the actual wavelenght of green but 520-530nm ones, the most usual found due their better lm/W (burned watts) ratio, are about 530lm produced per optical watt.

The best white LEDs in the market produces near 150lm/W (burned Watts). While the best green LEDs are about 100lm/W, but as they have improved fast lately, most green LEDs are about 80lm/W and white ones about 90lm/W.

In order to know the radiometric efficiency of a given LED, you just need to divide its lm/W (burned watt) by its LER (lm/W again, but refered to emitted watts). This way you obtain emitted watts/burned watts, the radiometric efficiency of a LED.

In the case of a typical white LED emitting 100lm/W and with a LER of 310lm/W, it means an efficiency 90/310=0.29=29%. In the case of a typical green LED emitting 75lm/W and a LER of 530lm/W, its efficiency is 75/530=0.14=14%, less than half light emitted per watt burned.

Those are actual figures of LEDs in the market (decent/good ones), but you have lower figures for other LEDs of both colors, actually. But in general you can expect double efficiency of current white LEDs over green ones.

For your T5s, green ones only have a little lower efficiency than other colors ones, as white ones. Nothing to do with half, as happen with LEDs right now. Similar efficiency, but still produces more lm per watt emited, thus the lm emission is way higher. But radiometric emission (energy, physical unit that rules plant's response) is almost the same.

 

[VerdantGreen]

thanks yet again knna - you have both the knowledge and the ability to explain things clearly and simply, which is quite a rare combination

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sooooo. plant is ready to chop any day i get time which hopefully will be tuesday at the latest. i have managed to swap the lights ready for the next grow, so the 104w custom light is now in a cab that measures about 2ft by 16". the original haze plants have been topped and supercropped and are now 'vegging' under a 12/12 light regime, and the day length will soon be reduced still further to 11/13 and then 10/14 in order to encourage them to start flowering. the plan is to flower just 2 plants in the cab and the rest will probably have to be cloned and wait for another round.
also i am working out a way to be able to scrog these plants, starting in a smallish pot and then moving to a bigger pot once they are flowering properly - this is meant to be the bets way to control the size of this strain indoors. i think i have a cunning plan for that

VG

 

[touchofgrey]

Hey VG, congratulations on another fine crop. You are getting the LED's dialed in quite well. Good luck with the haze, the stretch is a real challenge to keep under control in a scrog setup as I'm sure you know. I'm 70 days into a 100 day strain and still making LST adjustments. tog

 

[#1cheesebuds]

wow VG. holy moly thouse flowers r huge. so how many watts is ur led light system.

I might have to try this kind of light in the future. also how hot is it in the cab.

 

[SoMeGuY1337]

That is truly impressive, if only I could scratch up like 300+ dollars for something like that. Do I hear Christmas sell anyone?

 

[unthing]

Nice custom panel and beautiful plant. The quest for ideal spectrum and efficiency continues..One thing that has bothered me with panels and ufos is the noise of the fans, maybe not heard from the back of the cab or cupboard far way, but when you sleep in the same room, it's heard loud and clearly, heatsinks sound so much better for those of us who have to live in small/shared apartments (with roommates not with mom ), but maybe for many it's a minor detail. But anyways looking real good and interesting to see where this tech develops and when prices start to drop, couple of years maybe?

 

[coloradomedical]

That plant is just straight beautiful... I love it man, awesome grow.

 

[VerdantGreen]

touchofgrey - thanks - your grow looks good too

unthing, yeah i guess the fans make some noise but i imagine that in most grows that noise is going to be much less than the extractor fan and filter (certainly with mine). i guess the other possible advantage with fans is that you can 'recycle' the heat from the light fixture to help the plants. i have the intake at the top of the cab above the lights and the out-take at the bottom to do this.

cheesebuds - cheers - couldnt tell you exactly how hot the cab is but this custom light certainly gves out more heat than the standard ones.

SoMeGuY1337, coloradomedical , thanks guys.

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well, i finally got the plant harvested and have moved the light into it's proper cabinet that is about 2' by 16". seems to work well in there. the haze plants are installed and look like they have forgiven me for severely topping them. photos tomorrow if i can.

VG

 

[coloradomedical]

Can't wait for the photo's mate.

 

[Keif]

I may have missed it, but what do you expect for a dry weight VG??

 

[VerdantGreen]

thanks cm ill snap some dry nugshots of the SB too im a week or so.

hi Keif, i dont generally speculate on yield because it doesnt mean a whole lot
i doubt the grams per watt figure will be very high for this run because the light was too big for the cab - i was interested to see what size buds can be had from LED's at this high watts per square foot and they are certainly some handsome nugs for a scrog. doing scrog does sacrifice that one huge cola that you get with an untopped plant - but then you get plenty of medium sized ones. it'll be about another week before i have a final weight. i'll go and take a pic of the new cab now though

VG

VG

 

[VerdantGreen]

right - here is the new cab. not much to see. not pretty as its only in my loft anyway
mostly assembled lying on my back . above the door the cab is triangular due to the shape of the roof.

here is the inside with 6 original haze plants, topped and supercropped.

and one of the haze seedlings. they all look pretty similar except one that has slightly wider leaves - not necessarily indica but more dominant in a different tropical sativa - i can remember reading that one - maybe the colombian - had wider leaves.

cheers for now

VG

 

[coloradomedical]

Looks real good man... Someday I may have to take out my lighting in my cab in favor for these wonderful little lights. I definitely have the skills needed to make my own, it's simply the 300-400 dollar price tag on building your own.

Your grow looks amazing though mate.