Failing Project: Please Help!

[JoshuaDun]

Yo,

So to begin with I am very good at growing plants. I am not a noob. However when it comes to leds I don't know heaps yet.
I have had friends experience good success growing under leds so I began a small grow chamber & went with leds for various reasons. I planned to augment a slightly cheaper ebay light but since starting I have had no end of problems & its putting me off the whole idea of growing. :<

I am using a 480W Cree Chip COB LED Grow Light Full Spectrum

I reckon the 'cree' chips will most likely be seconds that didn't pass quality control or simply knock offs.

The problem is that the lights are far too powerful. The plants are being chlorophyll bleached quite badly. So to solve this I first tried using only 4 of the 6 lights. The plants just slowed growth & continued to be bleached.
So next I fabricobbled a dimmer switch & got the lights right down which is having the same result! slower growth & still bleaching.

I have now resorted to masking off some of the chips to reduce their strength.

I am now suspecting that it is UV damage not too high lumens.

I literally gave up on a plant out of frustration & planted her in the yard - now she looks better than ever.
I am just so confused why I would be getting bleaching & greatly reduced growth rates.

The attached pics show my first girl that yellowed as it got closer to the light & my newer yellow one.

Any advise would be much appreciated.

 

[Growingasmile]

Yo,

So to begin with I am very good at growing plants. I am not a noob. However when it comes to leds I don't know heaps yet.
I have had friends experience good success growing under leds so I began a small grow chamber & went with leds for various reasons. I planned to augment a slightly cheaper ebay light but since starting I have had no end of problems & its putting me off the whole idea of growing. :<

I am using a 480W Cree Chip COB LED Grow Light Full Spectrum

I reckon the 'cree' chips will most likely be seconds that didn't pass quality control or simply knock offs.

The problem is that the lights are far too powerful. The plants are being chlorophyll bleached quite badly. So to solve this I first tried using only 4 of the 6 lights. The plants just slowed growth & continued to be bleached.
So next I fabricobbled a dimmer switch & got the lights right down which is having the same result! slower growth & still bleaching.

I have now resorted to masking off some of the chips to reduce their strength.

I am now suspecting that it is UV damage not too high lumens.

I literally gave up on a plant out of frustration & planted her in the yard - now she looks better than ever.
I am just so confused why I would be getting bleaching & greatly reduced growth rates.

The attached pics show my first girl that yellowed as it got closer to the light & my newer yellow one.

Any advise would be much appreciated.

if you've done the same for both plants I would guess that the yellowing plant has suffered from nitrogen toxicity. Some plants eat more than others, if it isnt a feeding issue my second guess would be ph is off, are you p.h.ing your run off?

 

[JoshuaDun]

same growing media, same nutrients. :<

 

[Growingasmile]

same growing media, same nutrients.

every plant is different. if it worked for one plant and not the others the chances are you've over fed the other ones

 

[JoshuaDun]

cool man I shall dial down on the nutrient & see what happens in a week or so. I still suspect the lights as the yellowing disappeared after being planted outdoors & I am very frugal with fertiliser. Also both plants yellowed when the reached the same distance to the light.

 

[Chris Scorpio]

Hard to tell in the blurple lights and not nowing any pertinent info

Medium
Nutes
Water pH
Light distance from plants
Heat and Rh
Size of grow box/space

Could be any number of things not related to light

 

[JoshuaDun]

Sweet so its in 30lts of coconut coir with vermiculite & the tiniest bit of organic compost
Nuts in pic (no real schedule but pretty frugal)
Not sure of pH :< guess I should find out
Temp between 18˚C - 25˚C (64-77F)
Light is 800mm (31inches)
Pretty small chamber but is vented & circulated.

 

[Chris Scorpio]

Don't see any nutes

But if yer not pH yer water, umm, ya, that's a big potential issue for sure

How often do you water?
Nutes every water?
What strength of nutes?

 

[JoshuaDun]

sorry just edited my post to add the pics

 

[JoshuaDun]

A friend uses the same super grow/bloom with the same medium - no problems with growth. He probably adds more fert as its every watering.

 

[Grassmaster]

1 My Cobs are similar to sunlight. Yours look purplish.
2 The temperature should be about 78 degrees no less than 70 degrees.
3 When the plants are young they need about 300 PAR. When they are flowering they need about 800 PAR.
4 Some type of light meter is required. Other wise you really have no idea how far the lights should be from the plants.
5 When growing autoflowers use half the nutrients recommended.
6 Looks like you're killing your plants with too many different types of nutrients. Cannabis really doesn't need much. I mainly use Fox Farm products. I asked the guy at the hydro store if there was anything better and he said no. I use half of what is recommended on the bottles. A little organic nutrient like BIG BLOOM throughout the grow. Before flowering I might give them some GROW BIG. When they start flowering I stop the GROW BIG and add Tiger BlOOM. I also add a little CAL MAG especially when using LED's.

 

[fanleaf]

Your light, which is a mixture of lower grade small Cree Cobs along with the standard blurple is actually only a 200w light. Your issues are either environmental or nutrient related. Your not burning the plants that far away.

 

[JoshuaDun]

I agree that the light is in fact much lower wattage than stated & with sub-par chips at that.

Therefore other causes of bleaching would be Nut lockout from a bad pH (i'll get some strips as the pens are $$$), nitrogen toxicity as growingasmile suggested or a severely deficient nitrogen supply. The worst leaves are falling off almost by themselves so again suggesting a nitrogen issue. My friend uses the same medium & has no pH issues though.

I have undertaken an organic farming apprenticeship (ie have allot of experience with growing high brix plants & understanding soil science) so I imagined that the nut/environment could not be the issue.

Any thoughts? I am still confused as heck. What might you do to rectify issue?

 

[Chris Scorpio]

pH and nutes

Not familiar with yer nutes so can't comment on them
But generally 1/2 strength is plenty till u understand what the plants are needing

Keep in mind, because someone else is having success, your environment and processes are different, it can be frustrating to compare, so try not to and dive into your own situation

 

[Chris Scorpio]

How often do u water?

And is it with nutes , and what strength of nutes

 

[JoshuaDun]

HI,

So I've ordered a pH pen so I'll give that a whirl as soon as it arrives.
My nutrient is an organic liquid Guano (may be organic but it ain't sustainable or good on the environment). It is 10-10-2 & I am 5ml to 1l of water.
I water probably 3 times a week but generally trying get a feel for the weight of the pot to deduce how wet/dry it is.

Good advise on the comparing to others, tends to bring about misery.

 

[Chris Scorpio]

Coco is designed to be watered daily, with nutes each water, most water 2x a day or so in flower

It retains no minerals in it, thus the constant water. Its basically hydro growing

So, may reevaluate your process my friend

No clue on those nutes, but I'd see what yer buddy is using, and do the same strength wise, but water every day

 

[Growingasmile]

Don't see any nutes

But if yer not pH yer water, umm, ya, that's a big potential issue for sure

How often do you water?
Nutes every water?
What strength of nutes?

The wrong P.h. is an issue because it locks out nutrients, so when I say it's a nutrient issue I don't mean that it is 100% from over feeding or underfeeding but these are the most common mistakes aside from not getting the right p.h. wrong when it comes to yellowing leaves like this.

 

[Chris Scorpio]

The wrong P.h. is an issue because it locks out nutrients, so when I say it's a nutrient issue I don't mean that it is 100% from over feeding or underfeeding but these are the most common mistakes aside from not getting the right p.h. wrong when it comes to yellowing leaves like this.

Exactly

Bad pH can cause so many other issue for sure

 

[JoshuaDun]

Wow,

I knew coco was devoid of nut but not that I had to water that frequently. This really could be the case - under watering & therefore under nuts. This would be great cause I have the means to fix it easily!! I was considering buying a new light.
So glad I came here to get you guys advise. Thank you so much for taking the time to help.

I'll keep posted on the recovery & pH when I get my measuring tool.