Some of my plants don't like LED

TheSkyway

TheSkyway

Member
I have a weird one for you gents

I have 5 plants in a 4x4 grow tent in the 4 week range of veg. I run a 400w CMH HID for 20 hours a day, I then have a 450w Meizhi LED that I started putting on a timer to run about 10 of those hours. Yesterday it ran for about 5 hours and I noticed the of the plants were really drooping, it didn't make sense that it would need water because it had only been 2 days since they were watered. Temps were 79-80F as usual, only one fan blowing on them lightly. The led is also several feet above the plants as early on a few weeks back I caught the leaves fading under the LED just in time before they got bad.

I decided to turn the LED off, and the fan. 4 hours later the plant was perked right back up.

Then the same thing happened today. Only this time two of the plants showed these signs. Within an hour of turning the LED on


I'm not sure what to do about this issue, This is my first LED so I'm confused about what's going on and why the plants recover so fast just by simply turning off the LED
 
TheSkyway

TheSkyway

Member
I'm not real concerned about lights in the tent as I'm running a 400watt hid, 450 LED and adding a 150w HPS after I get the ballast wired.

My concern is my plants start drooping when the LED is turned on.and perk back up when it turns off. But have no issues with my HID. I'm just curious as to why this would happen
 
PetFlora

PetFlora

Well-Known Member
Odd to be sure, but don't assume all led has this problem. I never heard of Meizhi so I can't comment on them

LEDs can/do rock when using full spectrum with quality diodes and drivers

Since it's just one plant, seems like something in the fixture over that plant is the place to focus
 
Yodaweed

Yodaweed

Well-Known Member
It's because the CMH spectrum is more like the sun , so they most likely do not like that weird blurple color, i would get another CMH and sell the LED those things suck, the blurple spectrum always causes nutrient deficiencies because it's not really full spectrum, it's just two big spikes , one in blue , one in red.

If you have to use a blurple light, i'd suggest adding calmg to your nutrient regiment, your plant will need it.
 
ismann

ismann

Well-Known Member
Too much light.

You said yourself, the LED was causing the leaves to fade. That is first sign of light bleaching.

400 W CMH is more than adequate for a 4x4 in veg but I would try again in flower.

I did look up the LED on Amazon and it has good reviews but only pulls 195 W from the wall and 11.5K lumens. If you were using this as your lone light after the CMH, then of course they'll droop. Not nearly enough light and the plants have already adapted to the CMH. But the way you typed your OP sounds like you're using both lights at the same time which I don't understand.
 
ismann

ismann

Well-Known Member
I use a 600 W (250 W actual) LED in a 2x2 ScrOG and though it isn't hot or that much light, any closer than 12" to 16" inches and my tops bleach. Only thing I can really think of is LED panels with lenses on each diode are focusing all that light straight down. Some lenses focus a wide 120* beam but also 90*. I also have to raise the light if I use a reflector with HPS. My guess is they are drooping in response to a big change in their environment but they would probably get used to it after a few days. As I said, I'd try adding it back after a week in flower or so when they can use the extra light.

Also, you said the plants are around 4 weeks and yesterday they drooped. But you said a few weeks back, the LED was bleaching the leaves. If a few is 3, that would mean your plants were a week old under such an LED would surely bleach them.
 
TheSkyway

TheSkyway

Member
I figured the LED ran about 150-175watts as it is a cheapo. I only purchased it because I intended to run a small (2x3x3) tent but of course after years of not growing I got the itch and purchased the 4x4 and broke out the old magnetic 400w ballast. I enjoy the cooler temps and white light of the CMH vs HPS

I thought I could run the LED as a supplement light in the tent. It does have a "veg" and "flower" switch so maybe I'll just run it on veg and see how they respond. I'm assuming it will only pull about 90-100 watts with only one switch on.

Just FYI I already use cal mag in my nute routine, although I didn't realize it was necessary based on using LED so I appreciate that info.

Once I get the 150w HPS in the tent I may get rid of the LED all together. I'm currently in the process of separating the 150w ballast from the air cooled hood so I can put just the hood and bulb in the tent and not add the extra heat of the ballast. Just need to get a 14guage wire (extension cord) from the store to finish wiring it up.


I didn't think 400w would be enough for flowering in a 4x4 tent but if I add the HPS I'll be at 34w per square foot. Not ideal but I guess it will do
 
Yodaweed

Yodaweed

Well-Known Member
NaturalFarmer

NaturalFarmer

Well-Known Member
Yodaweed said:
Now that looks more full spectrum to me, not just two giant spikes. More like how plants evolved for millions of years using the sun, which is 100 CRI full spectrum, best light available and no electric bill.
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I think you are misrepresenting the graph. Where on the graph is photosynthesis driven the hardest with both chlorophyll a and b? How many nm? Which color do those two points produce?
 
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NaturalFarmer

NaturalFarmer

Well-Known Member
"Photosynthesis depends upon the absorption of light by pigments in the leaves of plants. The most important of these is chlorophyll-a, chlorophyll-b also plays a role.

................................................

It is evident that only the red and blue ends of the visible part of the electromagnetic spectrum are used by plants in photosynthesis. The reflection and transmission of the middle of the spectrum gives the leaves their green visual color."


http://dyna-gro-blog.com/the-difference-between-chlorophyll-a-b-and-photosynthesis-overview/
 
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N

NapalmZen

Well-Known Member
whitebb2727

whitebb2727

Well-Known Member
NapalmZen said:
https://www.reddit.com/r/microgrowery/comments/2nhcma/red_white_blue_full_spectrum_an_led_color_choice/

something for yodaweed. i posted it in a different thread. it tells you what spectrum's plants actually use.

TL;DR

blue is great for making a plant grow fast, but it needs to be shut off during flower

white/yellow is important as it naturally has a wide light spectrum. this is another reason COB work so well.

red is the most important color. not deep, not ir, and not pink.
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Blue is needed and used in flower.
 
N

NapalmZen

Well-Known Member
whitebb2727 said:
Blue is needed and used in flower.
Click to expand...

i am not a master at this and only have what others tell me or i read since most of the info is either beyond me or would require me to dump shit tons of cash into experimentation that i will never do. so, since this is all most of us have to go on, veterans included. ill just copy from the smartest sounding guy on the block.

What I mean is auxin and other plant molecules respond to non-red photons in a variety of ways, for auxin I mean less blue = more stretching, more flowering, for others like carotenoids, more non-blue = more activity. It's complicated but the general trend away from blue during flower is the way to go.
Click to expand...
 
whitebb2727

whitebb2727

Well-Known Member
NapalmZen said:
i am not a master at this and only have what others tell me or i read since most of the info is either beyond me or would require me to dump shit tons of cash into experimentation that i will never do. so, since this is all most of us have to go on, veterans included. ill just copy from the smartest sounding guy on the block.
Click to expand...
Auxins are affected more by topping or scrog than light. Apical dominance (Christmas tree structure). You break apical dominance to redistribute auxins for more yield.

It doesn't cost a fortune. I use a 8 bubl t5 and played around with spectrum. The more spectrum, the better in my opinion. At minimum a 50/50 mix of red and blue all the way through.
 
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