Red LED Light question - opinions please!

Hey all, noob here to the site! I used to grow back in the day (10 or so years), and have just gotten back into it. I'm a "professional" with no kids, so I have some discretionary cash so I bought myself a 32" x 32" x 60" grow tent, plus two 150 HPS grow lights. I plan on growing only 6 plants at time using soil, switching to 8 when I go DWC with the next grow.

I also bought four 660nm red LED panels which I plan to use to supplement the two 150w HPS lamps. The plan is to use these as vertical lights, hanging them down close to the base of the plant to light the lower nodes. Each LED panel is 12" x 12", and runs at 1620 lumens, which by my math puts me at just under 5400 lumens per sq. ft. Here's where I need opinions. What do some of you LED experts think of this system? Am I wasting my time/electricity with the LED panels? Do you think it will effect my buds in a positive way?

All opinions welcome since I'm a newbie to LED lighting!

What type of LED panels did you get? Have you considered growing with LED only? Initial costs are a little high, but with a ~50,000 hour lifespan, you save on bulbs and electricity.

mc130p said:

What type of LED panels did you get? Have you considered growing with LED only? Initial costs are a little high, but with a ~50,000 hour lifespan, you save on bulbs and electricity.

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I got them off ebay. Not too expensive, $60 per panel. They are 2nd gen LED's, 225 of them throwing 7.2 lumens ea. I considered straight LEDs for a long while, but after some research and cost analysis, I thought HPS would be better for the money and output. I view LED's as more of a supplemental-type of light (adding blue or white panels during veg, red during flowering). They are low heat so they are easy to hang vertically down near the base of your plants so it throws light down near the lower node sites.

So I guess it was basically cost versus output. I could not see myself laying out big money for a top-of-the-line LED system that still would not be as good as an HPS, even given the long term costs in electricity.

Doesn't HPS have enough red?

I built a 300W LED panel and we're supplementing with a small halogen for the added red. The Cree White LED's poop out after ~700nm.

The panel:



The Halogen:

Rrog said:

Doesn't HPS have enough red?

I built a 300W LED panel and we're supplementing with a small halogen for the added red. The Cree White LED's poop out after ~700nm.

The panel:

View attachment 2734600

The Halogen:

View attachment 2734601

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Yes, the LED panels are more for that lower node growth. I can hang them vertically down near the base of my plant, inches away. It throws a lot of extra red light down at the lower nodes.

Ah. Interesting. So does the red have less penetration vs blue?

Rrog said:

Ah. Interesting. So does the red have less penetration vs blue?

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Not really sure, I think it probably depends on lumens. The LED Panels are low profile - only 1 1/2" thk by 12" square, so I can hang them straight down near the base of my plants, within inches without having to worry about them burning the plant. As you know HID lamps can be hot, so you can't get them as close to your plants. They also dissipate light quite a bit over certain distances, so if you have your lights say, 18" from the tops of your plants only the first foot or so of your plants are getting the high lumens. Past a certain point in dissipates, quite a bit if I remember. So the first foot or so of your plants may be getting say 1000 lumens, the next 6" maybe 600 lumens, the next 6" only 200 and so on. I figure with these panels I can get right down there in that 200 or so range and add some additional lumens.

Gotcha. wouldn't it also make the same sense to supply the under canopy with full spectrum, not just red?

Rrog said:

Gotcha. wouldn't it also make the same sense to supply the under canopy with full spectrum, not just red?

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I also gave this some thought as well, and almost went with red/blue mix LED panels instead. But they didn't throw off as much lumens (I think they were around 1300 or so), and my thought is I am getting enough of the whiter/bluer spectrum from the HPS.

This is my first grow with these, so I'm eager to see what happens. Unfortunately I won't have anything to compare them to, since I don't have a similar grow under the same conditions without the LEDs. I just hope I didn't waste my money on them, so I was curious if anyone else is supplementing with red LED's. I would not recommend them during all stages, I only use them during flowering. I add some CFLs during veg instead of the panels to give them some white and blue spectrum.

Rrog said:

Ah. Interesting. So does the red have less penetration vs blue?

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green has best penetration throough a canopy of leaves (cause leaves reflect high percent of green)
Red, esp deep red and far red travels best through air/water cause of longer wavelength. Think sunset light which is mostly orange\red.
I'd say red penetrates better than blue.

I would have gone with a blue red panel, rather than just blue. I use a couple of 28 watt panels to fill in extra light.

660nm is way over hyped

630 provides ~ 95% of the PS needed and last considerably longer than 660+ nms

I use WW led globes for below canopy lighting

Best Buy has a sale on 60w e WW globes this weekend $10!

Hi,
do you have some evidence to back that statement up?

Looking at photosynthesis Chloro A Peak @ about 670nm...id come to a different conclusion

PetFlora said:

660nm is way over hyped

630 provides ~ 95% of the PS needed and last considerably longer than 660+ nms

I use WW led globes for below canopy lighting

Best Buy has a sale on 60w e WW globes this weekend $10!


View attachment 2734940 View attachment 2734941View attachment 2734942

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Ah, I see you have the same idea as me, except your using bulbs, I went with panels. The LED panels I got are only 23w each, but they throw 1620 lumens. As far as 630nm vs. 660nm, I'm not too sure. For the panels I wanted in my price range, I didn't see any in 630nm. Hopefully 660nm will be OK, from my own research I think it will be fine. I guess the proof will be in the pudding when I harvest!! As I said, my only regret is not having a previous harvest to compare.

PetFlora said:

Most WW globes have ample 630

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I thought about bulbs instead of panels, but the panels I found were not only a good deal but have a slime profile at just over an inch thick. They also are super bright, which you expect from LEDs.

PetFlora said:

630 provides ~ 95% of the PS needed and last considerably longer than 660+ nms

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What? Can you please site this...? I need something better then: 'i read it somewhere...google it...'

I also gave this some thought as well, and almost went with red/blue mix LED panels instead. But they didn't throw off as much lumens (I think they were around 1300 or so), and my thought is I am getting enough of the whiter/bluer spectrum from the HPS.

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There you cant "think in lumens". Lumen correlates with the sensitivity for brigthness of the human eye and its amount of receptors for specific colours...plants could not care less about lumens....in other words: its just natural that red and blue have a "small" lumens value, but that doesnt say anything

sx646522 sadly he disappeared from the blogs. There are accompanying graphs that will not copy

As one can see, the CREE Neutral White (I call it 'Goldilocks', because it's almost 'just right' ) has a RSPD that still allows nearly ~25% of its total power in the blue range (and plants only really 'need' ~8-10%), and more that 1/3 of which (i.e. the area under the curve) is over ~580nm or so (which has a Photosynthetic RS of over 90%!) - which is much better than even your typical 'Enhanced HPS'.


Couple that with strong white light (green-response chlorophyll extending throughout and deep into leaf structures, with a net effect at or near that of the (mostly) surface-level blue and reds), which also takes care of most of the ~660nm+ you actually need for photomorphogenesis - and you can get by with 630nm reds just fine.

(i.e. 630nm red is ~95% of the PSR of 660nm, AND they currently still have ~20-30% greater radiometric efficiency - as well as being cheaper than the deep reds - so there's more 'bang for the buck'):

whats this about the green light I read here everywhere? Do you have real sources, as in science? Because literature suggests that green light is actually inhibiting growth...
http://jxb.oxfordjournals.org/content/58/12/3099.full

ah well here they tell u something else
http://pcp.oxfordjournals.org/content/50/4/684.full