questions about realistic LED expectations...

I'm interested in getting the new A51 190 watt light. Looking at the PAR outputs it look like it should perform at least as well as a 400w HPS. A solid 400w HPS grower can pull around 400 grams. Is it reasonable to expect that the A51 can do the same? I've looked at journals of the 160 watt light and I haven't seen anyone beating 1 gram/watt. Sorry - I'm a noob and I'm sure this has been asked 1000 times. Can LEDs pull 1.5 g/watt or greater?

green.green said:

Can LEDs pull 1.5 g/watt or greater?

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No, but neither can anything else. 1gpw is difficult no matter what. I'd like to see examples of anyone getting 1.5gpw with anything.

I run a 357 mag in a hydro cab. It really only pulls half of that at 110 v so about 190. With an avg of 6-7 plants in a 20" by 3 ft cab floor and a height of 3.5 ft plants I pull 1.5 to 2 zips trimmed n dried per plant plus an 1/2 oz of trim n leaf per plant on avg. veg time is the key. I veg w supercropping, fim and ub topping and grow to 24" even canopy before flip. I don't time the veg, I use height as my guide .

Devilspawn said:

I run a 357 mag in a hydro cab. It really only pulls half of that at 110 v so about 190. With an avg of 6-7 plants in a 20" by 3 ft cab floor and a height of 3.5 ft plants I pull 1.5 to 2 zips trimmed n dried per plant plus an 1/2 oz of trim n leaf per plant on avg. veg time is the key. I veg w supercropping, fim and ub topping and grow to 24" even canopy before flip. I don't time the veg, I use height as my guide .

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How are you growing 6 or 7 plants in a 20 inch by 36 inch cabinet? I grow one in a cabinet that size and even then the thing is tight. Every time I try and grow 2 one always beats the other one out in size which I believe decreases yield for both.

Devilspawn said:

I run a 357 mag in a hydro cab. It really only pulls half of that at 110 v so about 190. With an avg of 6-7 plants in a 20" by 3 ft cab floor and a height of 3.5 ft plants I pull 1.5 to 2 zips trimmed n dried per plant plus an 1/2 oz of trim n leaf per plant on avg. veg time is the key. I veg w supercropping, fim and ub topping and grow to 24" even canopy before flip. I don't time the veg, I use height as my guide .

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So if I understand you correctly - you run a 190 watts unit over a total of 5 square feet. You average 38 watts/sq. ft. You pull around 330 grams from 190 watts. This is about 1.75 grams per watt. Do you feel the quality is better under an LED? What about flowering times?

Im real curious to see your setup Devilspawn as that would be astronomical numbers for any light but for an led thats just not been done and Id copy the setup if I can see it. Have a journel up showing this type grow?I am a bit confused though as you say its a cab that is 3 feet high but your plants are 3.5ft plus what every they grow in since your plant height is from top of medium to plant top which seems some how your getting over 4 feet of height in a 3 foot cab? Figure a pot at lo side is water 8 inches plus your 3.5 foot plant plus another foot for light space and hanging so thats 4.5feet tall in a 3 foot tall cab??? So your led is out doing a normal 600 watt hps light setup which is crazy amounts. I just wanna see this in a picture to understand it better. Thanks.

Sorry been tie up all day. I do have some early grows journaled with pics. The cab was a prefab full size two door metal cabinet originally outfitted with a shelf to do seedlings n clones. I have a 14 pot Rez set up over a tub that holds about 18 gal of solution with a recirculating drip feeder, airstone and a mister that I disconnected - it bathed root area in mist. For low humidity or seedlings it did work but also raised Rez temps. The mag 357 now hangs on adjustable hangers from top if 6 foot cab. The 357 does nor than ample coverage. Sometimes if canopy is crazy heavy I put a 90 w UFO I got with cab at bottom angled up to cross light lower buds and smaller plants if they are being shaded. For ventilation the cab had two input fans ( I disconnected n blocked one to maintain neg pressure in cab. It has a 4" exhaust fan n charcoal cartridge w ozone generator on output. But to answer questions above, I have run ak48, plush berry, widow and a few other hybrids

Sorry was interrupted. The plants get to a height of about 4 feet when finished. The tub is about 16", the light is pretty much hanging from eye hooks on top with quick clips and the distance from light to top total is about 8" so the finished plants can get right up against the light at times. I tie down those that are too close. The canopy with ub topping, supercropping and lst looks like sog before the flip. Each plant has the 4 main colas and 5-6 secondary from supercropping n lst. It's pretty much an even forest in there. The plants spread sideways to fill the entire cab footprint. Right now I have 7 plants in there, with one lagging a little ( lost og tude freebie). The bud quality despite what people say about led has been excellent. With the ak and tangerine dream I ran my last cycle , the ak had rock hard golf balls and the td main colas were a solid 10-12" of bud that dried down to 3 fingers thick. They are frosty as hell. In terms of time , I veg to about 24" 24/0 before flipping to 12/12. Flowering time is a bit longer than some advertise- td was done at 12 weeks vs 10, ak 48 at about 10 weeks. I harvest the top half of plants and let bottoms go an extra week I the trichs don't look done. I let the plants show me when they aRe done under a video scope.

Pic 1 is tub w 7 plants vegging. 2 is one td cola trimmed, 3 is tub w. Seedlings. 4 is a. TD cola or as friends n family say, that's a big bud

To answer the inevitable questions, I run gh nutes, I add big bud, bud candy and b52 early in flower. Ph target 5.8. Rez change every 2 weeks. One more porn pic. This pile pre trimming was from 1 td.

green.green said:

Do you feel the quality is better under an LED?

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Yes, IMO, medicinal quality is better under LED.
They've done some comparisons using the same cuttings grown under HPS and LED.
The LED buds end up with 2-3% higher THC levels.
I've been growing with LED's for over 3 years now and absolutely love them!
If you invest in the good stuff, like Area 51, you will be very happy with your grow for years to come.
I own one of their lights and am extremely happy with it.

Bad Karma said:

Yes, IMO, medicinal quality is better under LED.
They've done some comparisons using the same cuttings grown under HPS and LED.
The LED buds end up with 2-3% higher THC levels.
I've been growing with LED's for over 3 years now and absolutely love them!
If you invest in the good stuff, like Area 51, you will be very happy with your grow for years to come.
I own one of their lights and am extremely happy with it.

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Thanks BK,

I know the light is quality. I just want to have realistic expectations of yield. The PAR values from this light are greater than a 400 HPS - I wanted to make sure the yields were similar. This requires pulling 1.5-2 grams/watt. My sense is that with skill over 1.5 grams/watt is doable.

With skill n patience and knowing the coverage area of the light you will be fine. The 357 is oversized a bit for my cab and it replaced a black star 240 that had a electrical issue that took weeks to resolve . It is now a spare. Veg long enough and don't cut your flowering short. The potency n flavors I get are amazing.

Thanks Devilspawn - I'd take quality over quantity any day of the week. My area is saturated with mid-shelf medicine. I think top shelf moves east - I just know I don't see it.

green.green said:

Thanks BK,

I know the light is quality. I just want to have realistic expectations of yield. The PAR values from this light are greater than a 400 HPS - I wanted to make sure the yields were similar. This requires pulling 1.5-2 grams/watt. My sense is that with skill over 1.5 grams/watt is doable.

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Your not expecting 400w hps yields from a SINGLE 190w led panel are you? Because you better cut your expectations in half! Your coverage will be significantly greater with the hid, and skilled growers can flower up to a 4x4 with creative training/reflective materials.

1.5gpw is not easy at all, anything over 1gpw indoors takes dialing in your strain/ferts/conditions/high co2 levels/lighting/etc.....just because everyone on here's " SAY" their getting above 1 gpw with their panels doesn't mean it is so!

Fyi....I have never gotten over a 1 gpw with any hid, and yes this includes 600w hps(TBH I didn't weigh all my runs, still doubt it though)

PSUAGRO. said:

Your not expecting 400w hps yields from a SINGLE 190w led panel are you? Because you better cut your expectations in half! Your coverage will be significantly greater with the hid, and skilled growers can flower up to a 4x4 with creative training/reflective materials.

1.5gpw is not easy at all, anything over 1gpw indoors takes dialing in your strain/ferts/conditions/high co2 levels/lighting/etc.....just because everyone on here's " SAY" their getting above 1 gpw with their panels doesn't mean it is so!

Fyi....I have never gotten over a 1 gpw with any hid, and yes this includes 600w hps(TBH I didn't weigh all my runs, still doubt it though)

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PSUAGRO,

Have you ever grown with LEDs? I know 1 gram/watt is impressive with HID. I'm not sure the rules apply to the new LEDs coming out but time will tell. Not all watts are created equal. I'd be happy to pull a pound with 600 watts of HPS (and have). I would hope this is equivalent to 400 watts of high quality LED. So two A51 190w units, good genetics and good growing skills should be able to yield a pound. I'm not saying I'm the guy to do it. Considering the claims from manufacturers that a 150 watt unit can out perform a 600 w HPS - not so much.

I respect your opinion so if you think I'm off base please tell me.

If you can't do a GPW with an area51, you're doing something wrong.
I get a GPW easy with Advanced DS and Blackstar Chromes as well.

I've been looking into this myself (title of thread). I currently use 2 1000w hps and would like to switch to leds. If you look at the umole charts on the A51 site and the ones Greengenes/Tags posted in his thread on page 9(Tags high efficiency lighting garden) and compare them to what you'd be getting from a hps, leds seem like they should be killing it. But then you look at some of the grows people are doing, and although many of them are great grows, the yields just don't seem to be there like the umole charts suggest they should, so I'm starting to think there may be something missing.

I run 3 3x4 flood trays arranged in a 4x9 rectangle with 2 1k lights (in a 5x10 tent). Perpetual harvests. My worst run (single 3x4 tray) was 20 zips, my best was 26 and I don't even have it dialed in all that good(if you do the math I'm hovering around 1gpw).

2 A51 lights would fit perfectly over each flood tray, yet for the yields to be comparable I'd have to be getting a minimum of 20 zips with a lot of room for improvement. That's 10 per panel (or 1.5 GPW minimum). Looking at the specs it seems easy to achieve, but I'm just not seeing people actually hitting those #'s. (But to be honest I haven't been looking real hard, still trying to learn the "science" behind the technology).

One thing that crossed my mind is I've read that the plants don't uptake nearly as much water under led's as they do hid. It's been said as a good thing, but it makes me wonder if that reduced uptake means they're not uptaking enough nutes to get the yields we see under hid lights.

Hopefully someone will chime in and point me in the right direction because I really do want to make the switch, just not at the cost of reduced yield.

I run two 350W DS XML LEDs on my aeroponic setup with 30 plants right now. They are almost through the second week of flower. A little over 3 ft tall and 66 solid colas I can count on top. Don't bother comparing Watts between LEDs and HPS - I am getting much better yields with this two 350W than I did with two 600W HPS. Quality of the LEDs matters too. I paid $1K for each of these XMLs and they are great for SOG. But LEDs have smaller coverage area than other types of lighting so it can get very costly to light up a large grow. But if you have the money there's no competition in my opinion.