Leaves Yellow Faster Under LED's

Delps8 said:
The plants are short and compact which is a sign that, at some point, they got good light and/or that they received a lot of blue photons.

What are you using to measure your light output?

Just by eyeball, I'd say that the hang height has got to be at least 36". Even a 1k watt LED doesn't put out a lot of light at 36".


Re. yellowing and LED's - it's not an issue of the lights. There are lots of LED's in use for all sorts of agriculture all around the globe. If you're running into issues, you might post some photos, nute info, light (model, hang height, dimmer setting, and schedule) nutrients, watering practices, etc. so that folks can help diagnose the issue. It's frustrating to have a grow go sideways but there's lots of help here.
Click to expand...
If I had hung those lights at 36" the plants would have been completely fried even quicker than they were, those are Kingbrite Lm301h quantum boards 3000k and they were hung as high as they could be in the tent and I didnt even have them on full power, only in half.
I normally use BioBizz allmix for my grows and I don't begin fertilizing until a week after they begin flowering and I use biological nutes like bat guano and worm castings, etc.
I guess I just haven't got the knack of flowering with led's, have seen some fantastic grows on this forum using led's just can't figure out why they arent facing the same issues thats all, its a head scratcher for sure 😵‍💫, anyway happy with my Hps, I know where I am with them and they still bring results, sometimes I add a blurple led next to them which definitely improves the yield.
 
Delps8 said:
You're not giving your plants very much light. If the photo that you posted is the actual grow tent, it's dark in there.

Here's a picture of my current grow. Compare the brightness in the tent in this photo to the one you posted.

I'd love to get the specs on your light and your set up - the actual board and the measured hang height - because, based on what you've posted (the info about the board and the picture of a dark grow tent) it's a tribute to cannabis that it will grow so well with so little light.


1728744437669.jpeg
Click to expand...
The whole point of using a grow tent with reflective walls as opposed to having your plants in the middle of an open room is that a grow tent prevents your photons of light from escaping and dissipating as they would do in an open room meaning the light is trapped in your tent and just bouncing around off the walls like crazy which in effect allows you to hang your lights higher.
The tent might look dark to you but trust me it wasn't. And if I had hung the lights any lower like you suggested they would have fried even faster and no, NOTHING to do with any "negligence" on the part of the grower as I have been growing probably before you were even out of your diapers.
 
bluter said:
i'm leaning toward this being the issue more than anything





as noted it's a kitten brand. i would not count on the components being legit. ali baba is mostly known for fakes and knockoffs. i would have to seriously check that board to determine whether or not it was fugazi.

every fake claims to use lm's. and that's not even taking into account the drivers and other components.
Click to expand...
If you do a quick search on this forum or indeed other cannabis forums you will see examples of fantastic grows using this very same quantum board, nothing wrong with them.
 
aphrodisia said:
The whole point of using a grow tent with reflective walls as opposed to having your plants in the middle of an open room is that a grow tent prevents your photons of light from escaping and dissipating as they would do in an open room meaning the light is trapped in your tent and just bouncing around off the walls like crazy which in effect allows you to hang your lights higher.
The tent might look dark to you but trust me it wasn't. And if I had hung the lights any lower like you suggested they would have fried even faster and no, NOTHING to do with any "negligence" on the part of the grower as I have been growing probably before you were even out of your diapers.
Click to expand...
Best of luck with your grows.
 
I have been pondering my yellowing leaf issue and I think I may know what the problem might be after analyzing all things. As stated nothing has changed but the lighting (HID to LED). This is not entirely true. The flowering plants NOW are much smaller (1/3 to 1/2 the size I normally grow em). I'm thinking now 1-that since I water when the pots are light (usually 3 days) for my normal sized flowering plants and usually 5 days for these smaller plants before the pot is light. SO I'm thinking they are using N first and are out of it by the time the pot is light thus causing the yellowing sooner. I think I have to water more often (as Bluter said) even tho the pot isn't light yet. Wonder if that's why they say you can't over-water a hempy bucket?

Any opinions?/thoughts?
 
BigBudsBunny said:
I'm thinking they are using N first and are out of it by the time the pot is light thus causing the yellowing sooner. I think I have to water more often (as Bluter said) even tho the pot isn't light yet. Wonder if that's why they say you can't over-water a hempy bucket?

Any opinions?/thoughts?
Click to expand...
Interesting ideas worth thinking about.

One of the reasons I say that that growers should be always asking themselves questions.
 
BigBudsBunny said:
I have been pondering my yellowing leaf issue and I think I may know what the problem might be after analyzing all things. As stated nothing has changed but the lighting (HID to LED). This is not entirely true. The flowering plants NOW are much smaller (1/3 to 1/2 the size I normally grow em). I'm thinking now 1-that since I water when the pots are light (usually 3 days) for my normal sized flowering plants and usually 5 days for these smaller plants before the pot is light. SO I'm thinking they are using N first and are out of it by the time the pot is light thus causing the yellowing sooner. I think I have to water more often (as Bluter said) even tho the pot isn't light yet. Wonder if that's why they say you can't over-water a hempy bucket?

Any opinions?/thoughts?
Click to expand...
By mid flower I was topping up the hempy reservoir every day !

Cheers
 
aphrodisia said:
Thats the main reason I don't use Led's on their own when flowering and always place an hps bulb next to them.
I have tried (a lot !) to veg and flower with just led's on their own but I always run into this problem of yellowing once I flip them into flowering. Led's are brilliant for vegging but when it comes to flowering boom !, around 2 to 3 weeks into flower the fan leaves begin yellowing and drying up and once the process starts there doesn't seem to be much you can do about it no matter what you try 🤔 eventually I just got fed up wasting time and money only to watch my plants slowly dry up so I just stick to my mh/hps combo now, at least I know where I am with those, guess I'm just old school 🤨.
I see lots of fantastic grows on this forum from people using led's and I have to wonder how the hell do they do it ? Beats me.

Day 50 day 21 of flower D.jpg

Day 50 day 21 of flower D.jpg




Above is an example of what I mean. I was using a quantum board for this grow and everything went swimmingly well during veg, you can see how bushy and healthy they look in the photo but 3 weeks after flipping them the problems began, leaves began crisping up and yellowing, if you look closely you can already see them yellowing. I tried everything from calmag, etc. but nothing helped and I just watched helplessly as they slowly withered. No more led's for me, I'm done.
Click to expand...

You're using the LED fixture as if it was a HPS, which isn't how it's utilized. You need to look at the reccomended hanging height to dial in your ppfd, most of the time it's 12" to 18" during flowering.

I can't tell you why your leaves are yellowing, but I'm wagering it's not the light either way.
 
Back
Top Bottom