Home Depot Cree - distance from canopy

I use normal Cree LED (9W 5000K) in my veg cab. I broke off the glass covering as well. I have always treated them basically the same as CFL and pretty darn close to the canopy.

I'm growing a strain for the first time and having some challenges. Normally I get the nute regiment down by the end of the first grow of a new one but not this one.

In any case, I am just curious how far from canopy they should be and if they were too close, what would the impact be? I've googled light bleaching and that is not what I am seeing. Mine looks more like a Calcium or Manganese deficiency which should not be the case. So I am wondering if somehow there is a connection.

GrowinDad said:

I use normal Cree LED (9W 5000K) in my veg cab. I broke off the glass covering as well. I have always treated them basically the same as CFL and pretty darn close to the canopy.

I'm growing a strain for the first time and having some challenges. Normally I get the nute regiment down by the end of the first grow of a new one but not this one.

In any case, I am just curious how far from canopy they should be and if they were too close, what would the impact be? I've googled light bleaching and that is not what I am seeing. Mine looks more like a Calcium or Manganese deficiency which should not be the case. So I am wondering if somehow there is a connection.

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Pics would help, but in my experience, there is no such thing as "too close" with those bulbs...what do the defincies look like

I haven't broken the globe off my Cree A19s, but I have had some burn with the leaves touching the globe for a long time. Other than that, 1" doesn't seem to be too close. I use a reflector with my A19s. 1" hasn't been too close.

I've got Cree PAR38 (19w, 90w equiv spot and flood). Those need some more distance. The spot needs about 12". The flood about 6-8".

Post pics!

az2000 said:

I haven't broken the globe off my Cree A19s, but I have had some burn with the leaves touching the globe for a long time. Other than that, 1" doesn't seem to be too close. I use a reflector with my A19s. 1" hasn't been too close.

I've got Cree PAR38 (19w, 90w equiv spot and flood). Those need some more distance. The spot needs about 12". The flood about 6-8".

Post pics!

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Is using cree spots and floods comparable in efficiency to building a small DIY panel using say 4-5 Vero 10's?

Here are some pics. Some leaves get it and pretty quickly are ready to be pulled. My soil mix is unchanged. Same DynaGro nutes as always so I am not fucking with a bunch of stuff. Nothing different from prior grows except new strain (Barney's Blue Cheese).

GrowinDad said:

Here are some pics.

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Looks to me like you're not feeding enough. They look starved. If you were in flower I'd wonder if you have salt buildup causing nute lockout. I guess that's still a possibility, but my mind doesn't go there because it's usually seen a third of the way into flower.

If the only thing that's changed is the strain, I'd bet on it being a heavier feeder. I'd increase the feed by 30%. Also, measure your runoff ph and ppm. The trend of those readings will let you know if you're overfeeding and getting salt buildup.

EDIT: You might wait for someone else to confirm this. I haven't had too much underfeed experience. I usually have the opposite problem.

They are a little underfed right now because I laid down the nutes a bit trying to get dialed in. There really should not be any salt buildup though. I run with good runoff, use Drip Clean in all feedings, etc. In any case, that is what has me exploring. These are clones of the first run which will harvest any day now. Using Cal-Mg vs the Dyna Mag Plus seemed to help. But I have been doing the same on these and it is appearing.

DonPetro said:

Is using cree spots and floods comparable in efficiency to building a small DIY panel using say 4-5 Vero 10's?

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I don't know. I doubt it because COBs are reported to be significantly more efficient. Maybe @FranJan would know. He has used the PAR38 spot for awhile.

DonPetro said:

Is using cree spots and floods comparable in efficiency to building a small DIY panel using say 4-5 Vero 10's?

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The commercial Crees that I have seen are about 80lm/W in warm white (which includes driver losses and diffuser losses) so we could call it 100lm/W equivalent, that is about 31% efficient. The Vero 10s could be run at about 35% for an economical price, and up to 40% if you double the cost. But that price it is CXA territory, with Z4 bin you could get 47%

GrowinDad said:

I use normal Cree LED (9W 5000K) in my veg cab. I broke off the glass covering as well. I have always treated them basically the same as CFL and pretty darn close to the canopy.

I'm growing a strain for the first time and having some challenges. Normally I get the nute regiment down by the end of the first grow of a new one but not this one.

In any case, I am just curious how far from canopy they should be and if they were too close, what would the impact be? I've googled light bleaching and that is not what I am seeing. Mine looks more like a Calcium or Manganese deficiency which should not be the case. So I am wondering if somehow there is a connection.

Click to expand...

You can get them close as touching with the globes ON. With them off, I imagine you will have physical damage if a diode is touched when on. I don't really ever get bleaching even when I get lazy and leave them around 1" of distance [it happens].
Normally, I try and aim for aroud 4-6 inches in flower. Although I have been experiencing some foxtailing from 2 out 10. Could be from other factors, but I have tweaked soil recipes and still catching it a bit. 110 watts in 3.5 ft/2.

I have flowered them easily around a 1 foot over the canopy. Not as intense obviously, but that gives you an idea of extremes...

[realized I am not showing my naked cree bulb, but the Phillips bulb is naked and plants have never bleached even 1" under that sucker: 3000K 10.5w.....]



@DonPetro This is my last run with bulbs. Also switched another cab from Cree bulbs to a [6x] Vero10 3500K setup. For certain types of cabs, Vero10's are really nice for spreading the canopy out. With a recycled heatink and drivers from Fasttech, I spent about $50 overall for a 40w [+-5] light, that on paper, is averaging about 120 lumens per watt @265-300ma.

The cabinet pictured above is getting [2] Cxa AB3070's, and measures 27" x 19" in the floor and about 32" in height.

I have alos thought about going with: 12x Vero 10's, 3 apiece on a single 2.08" heatsinkUSA. So 4 sinks of 12" each, covering my 3.5sq. ft. And in 4 drivers from Fasttech and a small fan/ps setup.
This would cost me about $175 with shipping for every little doo-dad. While the Cree's probably would run less with $15 ebay drivers and $10 Arctic coolers....the spread of the Vero's would be superior in this type of low ceiling, fairly squat floor setup........however....... I already bought the AB's

The only place I still use the Cree bulbs is over my cloning buckets and my early veg area. Can't justify using something that is omni directional at a little over 80 lm/wt when I have better options.