Deficiency or burn?

Hi,
I am starting to have a problem with my plants in dwc.
The plants have been fed the lucas formula so far, the last couple of weeks ppm has been around [email protected] which I think should be 1.6EC PH has been dropping slowly instead of going up like it has been from 5.8 to now at 5.3.
the temps are around 27C/80F for the canopy and about 21C/70F for the water.
The plants are at their 12 weeks of flowering and the strain is a sativa from oaxaca mexico.

I have noticed leaves yellowing lately.
I must admit I kept them at a lower ppm of about [email protected] and I went up just lately thinking it might cure the problem.
Am I barking off the wrong tree, am I burning the plants?

here are some pictures of the yellow leaves please somebody help me as I would like to do a res change tonight and don't know if I should go high or low on nutes.
View attachment 30381View attachment 30382View attachment 30383View attachment 30384

Can you get us pics of the whole plant? from right now it looks like a nute def, but if it's burn most of the new green leaves will have a very tiny yellow tip on the leaves if you're starting to burn them. This sill stop(not go away) once you start feeding correct nute dosages. Remember, a nutrient def USUALLy starts at the bottom, and nute burn affects the whole plant equally.
first off, where is this yellowing right now, and where did it start?

have a look here https://www.rollitup.org/grow-journals/17913-tale-possible-oaxacan-bagseed-10.html#post293458for the pics of the whole plant.
I am starting to think it might be N deficiency. please let me know what you think

ok, what sk3tch said is good, flush once but immediately feed. what is the NPK of your fert?

It looks like you might have a mix of a calcium def and an N def. do you have hard or soft water? and does your fertilizer contain any calcium?

it's fairly hard water and I am using gh nutes, not sure how much calcium is in there, but have kept them low, maybe not enough calcium when they are low?
I will give them full strength tonight and see how it pans out.
thanks for the input.

If anybody else has any other input please feel free

There would appear to be lots of white spots on your leafs that look like your plant has been attacked by mites or mould i cant really tell properly from these pics.

You can see this a lot on the second pic.
Inspect the underneath of your plants leaves with a magnifying glass to check for mites.

If you have mould you need to seriously cut the humidity in there and let them dry out or it will ruin your weed or they may just be where your camera flash has gone of and reflected the small dead parts of your leaves.

P.S. you do have a small amount of nute burn i can see it on some of the tips but its not severe,severe looks really yellow and brown and goes all crispy

ok now I am really confused, is it burn or deficiency? I have just changed the res to full strength, don't get me worried now
I guess I will see the reaction in the next few days but you guys are puzzling me now!!
I'll check for bugs too and yes there are white spots...
damn I am so close to the end it would be a serious downer if something at the end would ruin the whole journey

gigi999 said:

it's fairly hard water and I am using gh nutes, not sure how much calcium is in there, but have kept them low, maybe not enough calcium when they are low?
I will give them full strength tonight and see how it pans out.
thanks for the input.

If anybody else has any other input please feel free

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I would listen to K and sk3tch3, flush and then feed. Also what k said is right most of the time. Def starts at the bottom, burn all over. And a good product for Calcium is something called Cal/Mag it's made by Botanicare. Best of luck

No if i were you i would listen to me the yellowed leaves are not at the bottom,the white spots are bugs or mould and you have overfed those plants as i have inspected blown up versions of your pics and nearly every leaf in your pics have tips that are nute burnt.

Dont confuse my post count with me giving you wrong or bad advice,i have over 20 years exp,if i don't know something i wont comment simple as that and i would never type something that was crap

Flush the plants check for bugs,add a couple of tabs of alka seltzer to a gallon of water let that run through use some weak soap and water solution to kill mites if you have any and decrease the humidity if its mould and cease watering for as long as possible,your plants aren't that for from harvest anyway so you should be fine.

that's not bug damage and mold needs dead leaf tissue to manifest itself, and there isn't any. He'd have random necrotic spots if it was overfeeding and the leaf tips would be more burnt if it was overfeeding, and the pattern of yellowing suggests a deficiency.

kieahtoka said:

that's not bug damage and mold needs dead leaf tissue to manifest itself, and there isn't any. He'd have random necrotic spots if it was overfeeding and the leaf tips would be more burnt if it was overfeeding, and the pattern of yellowing suggests a deficiency.

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guys are these random necrotic spots?

kieahtoka said:

that's not bug damage and mold needs dead leaf tissue to manifest itself, and there isn't any. He'd have random necrotic spots if it was overfeeding and the leaf tips would be more burnt if it was overfeeding, and the pattern of yellowing suggests a deficiency.

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Well in my opinon the leaves are dropping because hes near harvest,he has overfed it slightly and mould can pop up at anytime depending on his environment.
Until he inspects the plant himself with a magnifier we wont know for sure if its mites or mould or camera flash.
I already said add some alka seltzer for the obvious deficiency

gigi999 said:

guys are these random necrotic spots?
View attachment 30439View attachment 30440

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Those close ups are easier to see that its just a deficiency and the fact that your buds are draining your leaves,its not mould and not mites by the look of those close ups.
Just flush it through with some clean filtered water with a couple of tabs of alka seltzer per gallon that you use

ok I'm glad you are looking at it now, unfortunately I have just given full strength nutes.
Now, you say that you can clearly see it's a deficiency yet I should flush?
Is that because I am close to harvest?
And what you mean alka seltzer? the real thing? as the medicine?


PS should I just at least for tonight dilute the solution in the tank?

gigi999 said:

ok I'm glad you are looking at it now, unfortunately I have just given full strength nutes.
Now, you say that you can clearly see it's a deficiency yet I should flush?
Is that because I am close to harvest?
And what you mean alka seltzer? the real thing? as the medicine?


PS should I just at least for tonight dilute the solution in the tank?

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Yes alka seltzer the medicine,and to be honest you have only a small amount of nute burn so i wouldnt even worry so much as you are.

The alka seltzer will help with any mag(causing yellow leafs) deficiency's you have and clean out any nitrogen/calcium deposits that are clinging to the roots and making it harder for them to take up what they need.
This is a pic of one of my plants that is 24 days into its 12/12 cycle.

Its mainly sativa so it will go for 12 weeks 12/12 if you look at my pic youll see that i am a good grower and this plant has had alka seltzer.
Never use to much though or to often,2 tabs in a gallon once every 4 weeks is plenty.

So in short, is it nute burn or deficiency?

your plant looks great by the way. I know by now you can grow them right

All I want to know is should I go easy on nutes from now till harvest or should I go the other way? what would you do?

Well i grow in soil and your not so to be honest im not sure as your using dwc and i dont know if they need constant feeding or not.

I personally feed mine nothing for the last 2 weeks except water and mollases and then in the last week i water them only just enough to keep them from drooping then i leave them in the dark with nothing at all for 3-5 days before i chop them down.

As to the nute/def question imo you have both,slightly overfed but not to much and a slight deficiency.

If you have more than 2 weeks to go use the alka seltzer if not just flush them through with clean water and use some kind of carb product thats suitable for dwc grows as i don't know if molasses is suitable for them or not

is that alka seltzer instead of epson salts for MG deficiency?

ravenmyst said:

is that alka seltzer instead of epson salts for MG deficiency?

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Yes it is