Problems with LED vs. CFL

az2000 said:
I didn't understand that. Water heaters have whatlled a "sacrificial anode" which will erode before the tank's steel liner. I don't believe it erodes at a rate that it would provide significantly more mg than your tap water would have in it anyway. (The rod could be aluminum, not magnesium too.).

If it were me, I'd spend $2 on a pound of epsom salt at the drug store. Use 1/4 to 1tsp/gal nutrient solution depending on severity of mg def. It will last a decade at that rate of application.
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Got some today, i planned on using epsom initially but the stores were closed and i was high and impatient last night...it felt like the more I looked at it the worse it got
 
cal-mag+ is dumb.

It's just watered down calcium nitrate, magnesium nitrate, and chelated iron.

You could get those individually, and use magnesium sulfate instead since it's cheaper and you don't need it in a stock solution, and same with iron sulfate vs chelated. Iron sulfate is fine as long as it's not mixed in a stock solution with certain other chemicals, like boron. Iron sulfate (green) mixed with sodium borate (white) together turns into a black cloudy insoluble precipitate. Mixing in nitric acid causes it to turn orange and soluble.. too much info... hmm.
 
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The same thing happened to me when I started vegging with Area 51 lights a few months ago. My plants were dying. I was adding Calimagic at different ratios to try to fix it. That just adds more nitrogen, and makes things worse. Lol Now I don't add Calimagic or Epsom salt at all. I also run my nutrient regimen at half strength now. (Sativas) Excess nitrogen can lockout magnesium. I have to be careful with my new sativas.

I can't see your garden. But, I'm pretty sure smowstack gave you the right answer. In the end, I had my lights too close. At first, too far. Then, too close. The light was the size of my T5's. But, more powerful than HPS. I had to figure that out the hard way.

Try keeping them 18-24" for a while. And, feed them as normal. Hope that helps.

Peace.
 
I have some epsom salts, the calcium nitrate is on it's way ($10 for 4 pounds), I don't know what chelated iron is or what ratios to use at all but my plants are looking worse by the day. I'm wondering if this condition will continue when I flower with the cobs.
I've been trying one tsp per gallon of epsom salts for the past few days. No change. The thing about the calcium nitrate is I'm worried it'll be too much nitrogen, I'm already using dynagro foliage pro which is N heavy.
@Jeeyah So raising your lights fixed your problem? That might be an issue, I'm pretty height restricted.
I was hoping the led's would have a more vigorous veg than the cfl resulting in more buds but in the limited space I have the cfls perform pretty well.
I'm breaking my no picture posting policy. Any advice is welcome.
 

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It fixed my problem. I don't think you have a deficiency. I'm pretty sure 1tsp/gallon is too much Epsom salt. If you didn't change your nutrient regimen, you shouldn't have a nutrient problem. Sounds like the only thing you changed was the light.
 
churchhaze said:
It could be a coincidence, I'm not really liking my 5000k 70cri veg lamp either. The growth is just not as good as when it was under vero 3000k 80cri.
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Im surprised. I am running two veg lights. 5 x vero 10 5000k at 350ma each fixture. each one covers a 2x4 x 3' high area. I think Im less than six inches off the plants in spots and nothing but green growth. Explosive even. I find the stuff under 3000k for veg to be a bit lanky for my liking.


@tightpockt
I do use cal-mag. did not prior to using leds. I find they need a bit more nutrients in veg than they used to under cfl though. So maybe they are starved? Hope you get it fixed.
 
churchhaze said:
It could be a coincidence, I'm not really liking my 5000k 70cri veg lamp either. The growth is just not as good as when it was under vero 3000k 80cri.
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My 5k 70cri veg light does okay on its own. I've been leaving the small red boost on lately. That combo works pretty good. Ideally I wouldn't want to mess with small stars in veg though. I'd think at this point 4000k 80cri would veg best... Or, maybe just a 80cri 5000k. 70cri doesn't seem to have a very high light quality for plants

Just rambling on things I've possibly noticed..
 
SomeGuy said:
Im surprised. I am running two veg lights. 5 x vero 10 5000k at 350ma each fixture. each one covers a 2x4 x 3' high area. I think Im less than six inches off the plants in spots and nothing but green growth. Explosive even. I find the stuff under 3000k for veg to be a bit lanky for my liking.
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Interesting...I need to turn my reds off in veg again and look a little closer into it

What cri are your veros?
 
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Positivity said:
Interesting...I need to turn my reds off in veg again and look a little closer into it
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This is just my experience. They have been running 3 weeks now. I noticed a pretty significant increased nutrient requirement across the board compared to vegging with my cfl that were at 6000k. I used to be able to feed just water several times between nutrient feedings but now its every time.
 
SomeGuy said:
This is just my experience. They have been running 3 weeks now. I noticed a pretty significant increased nutrient requirement across the board compared to vegging with my cfl that were at 6000k. I used to be able to feed just water several times between nutrient feedings but now its every time.
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Same here, much less nutrient problems now. Keeping them in small pots bonsai style is easier than ever, just dial the light to just the right intensity.
 
SomeGuy said:
Im surprised. I am running two veg lights. 5 x vero 10 5000k at 350ma each fixture. each one covers a 2x4 x 3' high area. I think Im less than six inches off the plants in spots and nothing but green growth. Explosive even. I find the stuff under 3000k for veg to be a bit lanky for my liking.


@tightpockt
I do use cal-mag. did not prior to using leds. I find they need a bit more nutrients in veg than they used to under cfl though. So maybe they are starved? Hope you get it fixed.
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Seems we're running the same lights...You're running 5 @ 9 wattts for each 2x4 area? That's like 5 watts per square foot. I'm using 8 in a 1.5 x 1.5 area..geez, maybe that's part of the issue. I tend to over do it.
 
Does anyone know SPECIFICALLY what causes the Mg deficiency from LED (I believe its more Mg than Cal, I may be wrong)? I ran the exact same strain (clones) and within 1 week of flowering I ran into Mg deficiency whereas under HPS, I NEVER had Mg issues. Pretty crazy as I really did not believe it would happen, thought it was more of a case by case basis but it seems across the board.

Whats weird too is I grew for a short time with a PlatinumLED (P450) and NEVER had Mg deficiency issues. It worked under the same nute schedule was the HPS plants. Only 1 week in flower under my CXB3070 and I had Mg issues! It was easily corrected and better now, just a bit of a learning curve. Id really like to know what exactly causes it. People say "spectrum" but that is a poor answer and very vague. Trying to figure it out I just have not found any solid documentation.
 
doz said:
People say "spectrum" but that is a poor answer and very vague. Trying to figure it out I just have not found any solid documentation.
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I think what's meant by "spectrum" is that more umoles are reaching the canopy. Driving the plant's photosynthesis harder and creating a deficiency that didn't exist when there was enough mg to satisfy the photosynthesis occurring under lower umoles.

I think the difference between your COB and the Platinum is that the COB is more efficient, producing more umoles. I think the difference between LED and HPS is that you can get the LED closer and overdo the umoles compared to an HPS. I.e., it's just HPS's nature that you can't overdo the umules without burning the plants with radiant heat. It's a self-correcting problem. :) LED makes it easy to do the "more is better" mistake.

How many watts per sq. ft. do you run with your COBs? That's not as accurate as measuring actual umoles at the canopy. But, if you're doing something like 40w/sq ft with such an efficient light (or, have it too close) I think that would coincide with my theory.
 
az2000 said:
A photo would help. Mg def seems to be a common complaint from people converting to LED. Could be too close and bleaching the leaves. Is it only the top leaves?

If I were going to replace CFL, I'd use the Cree LED lightbulbs from Home Depot. Seems like a direct replacement with 30% more efficiency. With COBs I'd be concerned whether they're driven soft enough that they can be CFL distance (if you can't manage more distance).
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Which cree light bulbs at home depot provide good plant growth?
 
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