yellowing upper leaf tips

[Greenmile]

Hello all, I'm new on this forum, its my first post, but not my first grow project :)) , i need some advices from experienced growers, so heres my story :))

i have indoor growbox - 0.6x0.8x1.8, 0.5m2
im using CREE CXB3590 X2S with 200W power
nutrients: Fox farm trio
pots are 12L with perlite and peat moss, soil is very breathable.
temperature: 23c - 29c (sometimes 30 but its very rear)
humidity: 40 - 55
ph 6.2 - 7.0
for ventilation i have lot of fans on inteake and outtake, so thers no problem with that, growroom has very good ventilation.

problem is that leaf tips start yellowing or whitening, and it starts from higher leaves, lower leaves are all green, certainly its not some kind of deficiensi i think, because lower leaves are looking good, no yellow parts at all, this process starts in early veg and slowly develops through final stages of flowering, in the and from yellow tips, leaves turn 80 % yellow or orange, i'm a grower for 6-7 years and i have never noticed something like this before i started using led lights, i have checked ph, its 6.2 - 7.0 no issues with deficienci or overdose, ppm i s also good. before cxb i used galaxy hydro 300 and mars hydro 300, that was start of my problem, before i used cfls and HID s and have never noticed something similar, i also bought lux meter from ebay and started to use dimmer to control luxes per square meter, i started from 10 000 lux on seedling and than went to 30 000 lux in veg, on 50 cm height. this bulbs can produce much more up to 65 000 lux on 25-30cm height, and as i know plants can handle up to 70 000 75 000 lux, so i am i bit confused . cant solve whats wrong, the final product has very good taste and high and good buds, but i think plants go through some stress from light bulbs which affect on quantity of my harvest, in this growbox i take average from 170 grams to 400 grams , depending on strain types and quantity. and also forgot to mention that some strains dont yellow some do in same conditions, in same growbox. you can see it in pictures.

 

[Aqua Man]

Kinda looks like suffer to me... But the plants also look hungry in those last pics. You say ppm is good but what ppm are you feeding?

 

[Greenmile]

At this moment they are 35 days old from sprout, they are in veg now and solution which i give them is 900- 950 ppm, 2- 3 times a week, how much water should i give them or solution ? Pots are 12 L, mainly i watch for runoffs and try not to over water pots, but what kind of defficienci did you see ?

 

[Aqua Man]

At this moment they are 35 days old from sprout, they are in veg now and solution which i give them is 900- 950 ppm, 2- 3 times a week, how much water should i give them or solution ? Pots are 12 L, mainly i watch for runoffs and try not to over water pots, but what kind of defficienci did you see ?

It's kinda looking like sulfur deficiency. But it's not very common and would kinda lead me to to think it's more of a lockout issue.

I don't grow in soil so as per feeding and stuff wait for a soil guy to pop in. Maybe a flush and feed but wait to see what others say also because I'm not confident enough to say that this is the issue yet. Do you test ph and ppm of your runoff? It might give a better picture of whats going on.

 

[MIMedGrower]

Too often watering and too much nutes i think.

 

[MIMedGrower]

It's kinda looking like sulfur deficiency. But it's not very common and would kinda lead me to to think it's more of a lockout issue.

I don't grow in soil so as per feeding and stuff wait for a soil guy to pop in. Maybe a flush and feed but wait to see what others say also because I'm not confident enough to say that this is the issue yet. Do you test ph and ppm of your runoff? It might give a better picture of whats going on.

Yes I would leach pots with a gallon or two of fresh water. Confirm with the runoff. then pour through a complete balanced fertilizer at about 1/3 to 1/2 less strength than using now if actually needed.

 

[Aqua Man]

Are these pics all recent? Because the plants look different in several and I'm not sure if it's lighting.

 

[Greenmile]

Are these pics all recent? Because the plants look different in several and I'm not sure if it's lighting.

Those two littles in middle are 2 weeks younger, yes pics are recent i took them today, i use lst method.

 

[az2000]

pots are 12L with perlite and peat moss, soil is very breathable.

before cxb i used galaxy hydro 300 and mars hydro 300, that was start of my problem, before i used cfls and HID s and have never noticed something similar, i also bought lux meter from ebay and started to use dimmer to control luxes per square meter, i started from 10 000 lux on seedling and than went to 30 000 lux in veg, on 50 cm height. this bulbs can produce much more up to 65 000 lux on 25-30cm height, and as i know plants can handle up to 70 000 75 000 lux, so i am i bit confused . cant solve whats wrong,

Is it possible you used a new bag of peat moss this time? Peat can be acidic if not neutralized. Sometimes people get a bad bag of whatever their favorite medium is. (You said you checked the soil ph. So, this probably isn't a problem).

It sounds like you're convinced its the lights. You're comparing lumens as a sanity check. But, if the new lights produce more ppfd per lumen, that might be a false sense of security.

Your estimates for lux sound high to me. I recently bought a PAR meter and have been making a few comparisons to lux. I'm finding a conversion factor of 50 lux to 1 ppfd. I've read cannabis can have as much as 900ppfd in flower (after that, it's not as useable without co2, etc.). That would be 45,000 lux. (I arrived at this factor measuring ordinary household LED lightbulbs. The new bulbs are 50-52 lux to ppfd. An old one is 55, which woul be abut 50,000 lux in flower -- if the 900ppfd is indeed the max to use. Sunlight appears to be 66 lux to ppfd. That would be 60,000 lux = 900ppfd. But, I need to do that test again. ).

Did you arrive at your 70-75,000 lux when you used your HID and CFLs? If so, I can see how you might be giving too much light now, assuming the cxb is producing more ppfd, better spectrum, etc.

Since you think it's the lights, maybe dial them back to 45,000 lux for awhile and see what happens?

 

[Aqua Man]

Those two littles in middle are 2 weeks younger, yes pics are recent i took them today, i use lst method.

@MIMedGrower has ya covered... But you should also post results of run off. It will give some insight into your soil condition.

 

[oldskol4evr]

At this moment they are 35 days old from sprout, they are in veg now and solution which i give them is 900- 950 ppm, 2- 3 times a week, how much water should i give them or solution ? Pots are 12 L, mainly i watch for runoffs and try not to over water pots, but what kind of defficienci did you see ?

what????? those plant should be no were near a 950 ppm ,there your problem,full veg 450-700 ppm or 0.9-1.4 ec

 

[Aqua Man]

Is it possible you used a new bag of peat moss this time? Peat can be acidic if not neutralized. Sometimes people get a bad bag of whatever their favorite medium is. (You said you checked the soil ph. So, this probably isn't a problem).

It sounds like you're convinced its the lights. You're comparing lumens as a sanity check. But, if the new lights produce more ppfd per lumen, that might be a false sense of security.

Your estimates for lux sound high to me. I recently bought a PAR meter and have been making a few comparisons to lux. I'm finding a conversion factor of 50 lux to 1 ppfd. I've read cannabis can have as much as 900ppfd in flower (after that, it's not as useable without co2, etc.). That would be 45,000 lux. (I arrived at this factor measuring ordinary household LED lightbulbs. The new bulbs are 50-52 lux to ppfd. An old one is 55, which woul be abut 50,000 lux in flower -- if the 900ppfd is indeed the max to use. Sunlight appears to be 66 lux to ppfd. That would be 60,000 lux = 900ppfd. But, I need to do that test again. ).

Did you arrive at your 70-75,000 lux when you used your HID and CFLs? If so, I can see how you might be giving too much light now, assuming the cxb is producing more ppfd, better spectrum, etc.

Since you think it's the lights, maybe dial them back to 45,000 lux for awhile and see what happens?

Seen this before. Par to lux from my understanding is messy. PAR is better source of measurement. I think the type of meterss has something to do with it. Can't fully remember. He is only at 30,000 lumen though from what I read.

 

[Mrjay]

Looks like nite burn to me.
However I no these things are hard to diagnose correctly.if it was me I would flush with ph water and give it a couple days.
Are you de chlorinating your water?

 

[oldskol4evr]

your in peat right,you can flush i wouldnt,feed water next round let plant take what i can right now,there should be enough nutes in there to hold over to it mends,flushing peat gonna be mush and will compact

 

[Aqua Man]

what????? those plant should be no were near a 950 ppm ,there your problem,full veg 450-700 ppm or 0.9-1.4 ec

Yeah that's why I was asking about pics. Some look hungry and some look like nitrogen tox but lack of clawing kinda makes it look like sulfur or lockout. I'm not so sure on the feeding of soil so I'm sure between you and @MIMedGrower you can sort him out.

 

[oldskol4evr]

Yeah that's why I was asking about pics. Some look hungry and some look like nitrogen tox but lack of clawing kinda makes it look like sulfur or lockout. I'm not so sure on the feeding of soil so I'm sure between you and @MIMedGrower you can sort him out.

thats really high and im surprised it not worse ,which tell me that plant is a hog,those numbers a more early flower numbers,unless he trying to flip to flower and even then early bloom is 750-950 ppm 1.5-1.9 ec

 

[az2000]

Seen this before. Par to lux from my understanding is messy. PAR is better source of measurement. I think the type of meterss has something to do with it. Can't fully remember. He is only at 30,000 lumen though from what I read.

Sorry, yes. I was referring to what he thinks is the max lux in flower -- and then proceeded to suggest something as if he's in flower. But, he's not. Still, 30,000 could be too much in veg. From what I've read, 300-600ppfd in veg. 500ppfd would be 25,000 lux (according to my factor using the latest lightbulbs. CXB cobs could have an even lower factor.).

I think measuring lumens is safe as long as it's the same kind of light being compared. I think the problem is 50,000 lux with HPS might be low compared to 50 lux of top-bin CXB cob.

I agree with others that think it's deficiency or nutrient burn. But, it's odd that the OP has grown for 6 years and suddenly would have a problem keeping the soil too wet, feeding too much. With 6 years experience, I think his gut feeling about the lighting is significant.

 

[Greenmile]

thats really high and im surprised it not worse ,which tell me that plant is a hog,those numbers a more early flower numbers,unless he trying to flip to flower and even then early bloom is 750-950 ppm 1.5-1.9 ec

ok guys , so you all think ints not light bulb issue . . but more nutriet overdose
i will check runoff s for ppm and ph , should i do it with tap water or neutral water ? ill post results .

 

[oldskol4evr]

plant isnt struggling,i would just do water next feed,mistake is already made just have to eat the humble pie,im telling ya flushing isnt the answer,and lead to more problems down the road,flush before flower a couple weeks before is ideal in that mix,but again depending on the way you feed and have been i would go for a flush on them for sure if not now gonna be a salt build up,op goggle hannah feeding chart for cannibis,this will help in future

 

[Aqua Man]

Sorry, yes. I was referring to what he thinks is the max lux in flower -- and then proceeded to suggest something as if he's in flower. But, he's not. Still, 30,000 could be too much in veg. From what I've read, 300-600ppfd in veg. 500ppfd would be 25,000 lux (according to my factor using the latest lightbulbs. CXB cobs could have an even lower factor.).

I think measuring lumens is safe as long as it's the same kind of light being compared. I think the problem is 50,000 lux with HPS might be low compared to 50 lux of top-bin CXB cob.

I agree with others that think it's deficiency or nutrient burn. But, it's odd that the OP has grown for 6 years and suddenly would have a problem keeping the soil too wet, feeding too much. With 6 years experience, I think his gut feeling about the lighting is significant.

Changing lights also changes demands of the plant. Most LED growers seem to need more Mg I never really looked into why but I probably should.