Yellow tips, blotchy yellow spots - Nutes, light, or fungus?

[Kazooey59]

First - It's not unusual to sorta 'limp' across the finish line at harvest with ugly looking fan leaves. Most growers accept some yellowing (or worse) since you're pulling those leaves off at harvest anyways, as long as it doesn't get into the buds themselves.

As far as micros - Earth juice is basically a micro-only / micro-focused supplement intended for hydroponics - anything similar would work. You'd be looking for something with at least Zn and Fe on the label, and as little N-P-K-Ca-Mg as possible. Then, I'd probably say use about 1/4 to 1/2 strength of manufacturer's directions.

But, overall, it sounds like your plants may just be hungry for that P/K - not the other way around. That is, I'd be more concerned about a K deficiency than a K toxicity at this point.

Although there's a tolerance on the range and you don't need to hit the ratios exactly, a general rule of thumb is to provide K:Ca:Mg in a 4:2:1 ratio by weight. You can't really determine the relative ratios by EC alone - you have to go back and calculate/ballpark it from the label wt% of each element for each product that you're adding.

Canna A+B is 1:2:1, and the calmag would make the K:Ca side worse (even if it fixes the Ca:Mg side). Looking at the Canna feed schedule, reports from others pre-stage 2, and the fact that feeds for coco grows generally tend to be high Ca, it looks like Canna kind of rides the edge of low K / high Ca until the hit of K from stage 2.

As far as previous Mg issues, seedlings are more sensitive to feed variations than the adult plants. If you were having Mg issues during seedling, they may not (or take longer) to reappear now. And, I wouldn't worry too much about the upper vs. lower canopy distinction. It may just be an artifact of indoor growing vs. outdoor growing.

In the end, you may just be stuck with having to alternate calmag on/off during the grow until stage 2.

Silly question, but could you maybe create a reservoir mix fitting to my needs?

I am running 30L of water in my reservoir, with a base EC of 0.1, because I mix tap with RO. That's the baseline where I start. How much Canna Calmag should I add in your opinion? I am scared to go lower than 0.6, but I could try it for one reservoir-run.

The Canna Calmag Agent has a ratio of 4.9/1.4, which I still don't understand fully because they use %m/m, whatever that means, here's an image though:


Plants are currently mostly in the bulking stage, the nugs are getting fatter, pistils here and there are slowly turning brown. Day 60, here's an image:




Should I just lower the Calmag to a different EC this time? Or no calmag at all? It's kinda scary, considering that it's just 0.1EC without calmag

 

[Bruce Campbell]

For next reservoir, I would just use your normal calmag (based on EC), the normal Canna A+B dosage (based on EC), but then add half the recommended P/K from stage 2 and see if that helps. You'd just be adding the P/K based on the recommended volumes (mL/L) and letting the final EC be whatever it is. (Edit: You don't need to get exactly half of the P/K strength, just somewhere close.)

Then, you can decide whether to go to full P/K and/or start reducing calmag. In the meantime, you can also look around for a micro supplement.

 

[Mañ'O'Green]

Perhaps with such high variation in your tap water you need to test it each time before you use it to adjust your starting water? Or perhaps don't use it at all and adjust with Soluble Gypsum and AG Epsom.

RO water is hungry and will grab carbon from the air and lower the PH to below 5.5 if left alone. This is why you want to add some calcium (or any metal ions the plant needs) to stabilize it. I use soluble gypsum and AG Epsom salt to buffer mine .3g/gallon of each. This is going to just read on most EC meters as 0.1 or 50PPM Hanna and should be a fine starting point to mix your nutrients.

I have run over 2230 PPFD on plants less than 2 inches away from my ChilLed Growcraft Led fixtures without light burn, You are just is so unlikely to burn a plant under Led.




You don't happen to have a water softener on your tap water do you?

 

[Kazooey59]

Perhaps with such high variation in your tap water you need to test it each time before you use it to adjust your starting water? Or perhaps don't use it at all and adjust with Soluble Gypsum and AG Epsom.

RO water is hungry and will grab carbon from the air and lower the PH to below 5.5 if left alone. This is why you want to add some calcium (or any metal ions the plant needs) to stabilize it. I use soluble gypsum and AG Epsom salt to buffer mine .3g/gallon of each. This is going to just read on most EC meters as 0.1 or 50PPM Hanna and should be a fine starting point to mix your nutrients.

I have run over 2230 PPFD on plants less than 2 inches away from my ChilLed Growcraft Led fixtures without light burn, You are just is so unlikely to burn a plant under Led.


View attachment 1700075

You don't happen to have a water softener on your tap water do you?

My water is rather hard and loves to blast the PH all the way up to 8.1 whenever I lower it to 5.8 in less than 2-3 hours, it's just really funky. That's why I use around 25% of it in my RO water, to keep everything stable. That's what canna recommended me to do, to add bicarbonates for buffer capabilities. This causes my RO / Tap mixture to not lower, but just slowly raise in PH over a few days. I don't have a softener though, it's just straight up tapwater right out of some hundred year old pipes I imagine.

About PPFD - Yeah, it's still funky. I actually just made some new pictures of the "damage" I currently have on the leaves. Trust me, I have never seen similar damage in my life. I just hope it's not root rot. I pulled the copper root disc out of the bottom of the autopot with the problematic plant, had to turn it around and pull the pot off, which was actually easily done. I noticed a "fart" smell coming out of there, but the roots seemed white and healthy.

Here's the current damage:



Mentionworthy: This plant seems to be the slowest and not bulking at all. The leaves feel "soft to the touch", they don't have lots of stability, but she is drinking, and the leaves are praying. They're just missing.. stability? Just insanely soft. And as I said - No bulking. She seems to not bulk up like the other 3 plants, but she's getting the same food as all the others, as it's the same reservoir. Felt like this is worth a mention.

 

[Mañ'O'Green]

It is my personal experience that any metal other than stainless steel can cause toxic levels of metal to leach into the media. I know they make and sell them but they are supposedly Gold color coated ? They also suggest you use new ones for each grow. A metal toxicity could explain the strange minors lock-out we are seeing.

The sour smell is a dead giveaway for anaerobic microbes. I have witnessed many root rot problems with autopots, get some Botanicare HydroGuard and use it ASAP.

 

[BII]

Consider foliar feeding, at least with the Ca and Mg, and using Transport/Optic Foliar for better uptake. That way you can eliminate or reduce problems from adding cal-mag to your feed water. Foliar feeding will also generally resolve problems much faster vs. feeding the soil/media.

 

[Bruce Campbell]

It is my personal experience that any metal other than stainless steel can cause toxic levels of metal to leach into the media. I know they make and sell them but they are supposedly Gold color coated ? They also suggest you use new ones for each grow. A metal toxicity could explain the strange minors lock-out we are seeing.

The sour smell is a dead giveaway for anaerobic microbes. I have witnessed many root rot problems with autopots, get some Botanicare HydroGuard and use it ASAP.

@Mañ'O'Green - Is it just me, or are those leaves starting to look like copper toxicity?

Quick and Dirty deficiency picture depot (expanded to include other issues as well)

MOLYBDENUM: Mo; (mobile micronute)....absorbed as MoO4-- Leaves may become mottled or spotted. However, the tell-tale sign of a molybdenum deficiency is the leaves may start to display a unique orange, red or pink color around the edges which will start to move toward the center of the...

www.autoflower.org

 

[Mañ'O'Green]

@Mañ'O'Green - Is it just me, or are those leaves starting to look like copper toxicity?

Quick and Dirty deficiency picture depot (expanded to include other issues as well)

MOLYBDENUM: Mo; (mobile micronute)....absorbed as MoO4-- Leaves may become mottled or spotted. However, the tell-tale sign of a molybdenum deficiency is the leaves may start to display a unique orange, red or pink color around the edges which will start to move toward the center of the...

www.autoflower.org

It is a strong contender for sure. The answer is hidden in here but It is a devil to figure out.

Between the arrowheads is the allowable balance range and copper is tight on a few?

This shows some reactions with the major ions.

Because copper is antagonistic to Mg and Iron this could be what we are looking at because the leaves look kinda like a Mg problem?

I am just farting in the wind here

Speaking of farting a sour pot is a root rot problem and that needs to get fixed first. HydroGuard for the win.