Gelato Autos just in veg: leaves on one plant not doing too well

[Delps8]

The attached images are from one of four Gelato autos that are in day 23 (since germination). The leaves started showing signs of having an issue a few days ago. Only one plant is showing symptoms and only leaves that are being impacted are the lower leaves.
The grow environment is detailed in my grow journal here.
The plants went in the res on 10/02/21 and I did not swap out the res after a week, due to work schedule and due to the fact that it’s a 35 gallon//28 usable res and there were just 4 seedlings in the res. Air pumps were running for the two week period. Over that two week period, pH rose from 5.9 to 6.0, then to 5.9 and, yesterday, 5.8. Water temps are maintained at 68°.
VPD was 0.8-0.9 with ambient temps ranging from 76° to 82°. LST’s have been about -1° from ambient.
Nutes are Botanicaire Kind Expert and the EC was 0.4. I swapped the res today and the new EC is 0.8. I realize that’s a significant jump but I’m not seeing issues with any other plants and this issue existed prior to the change in the res.
As a precautionary measure, I swapped out 7 gallons of nutes. EC is 0.62, pH rose to 6.1 after the addition of 7 gallons of RO water. I added two doses of 1 ml each Down. The pH fell to 5.9 and, after the second dose, 5.7.
I’ve checked some of the visual "sick plant” charts and, so far, nothing seems to match the symptoms that I’m seeing.
The rest of the plant looks great as do the other plants in the res. Roots are lengthy, well developed, and white. The res had very little residue in it and still had that “fresh res” smell that we all know and love.

Seeking the wisdom of the group - what’s the diagnosis and what steps should be taken to resolve the issue?

 

[Delps8]

The leaves in the pictures were crisp and dry so I cut them off. Leaves from that (“Mutt”) plant indicate some issue - any ideas?
The second attachment is a picture of Jeff. Similar problem. Mutt and Jeff are the same strain from the same envelope but I germinated them a few days after the other two. Winnie and Mary are showing no issues.
Thinking that it might be light stress, I shut off the light for a couple of hours and will reduce the PPFD when they come back on.
DLI is 27, was at 6.0 for almost 48 hours but dropped to 5.9 overnight. I added 1 CC Down and pH is 5.7. I want to see if pH will continue to drop or if it will rise.
Any thoughts about this issue would be appreciated.

 

[Delps8]

More pictures of leaves on two plants.
Any help would be greatly appreciated.

 

[Krissi Carbone]

The attached images are from one of four Gelato autos that are in day 23 (since germination). The leaves started showing signs of having an issue a few days ago. Only one plant is showing symptoms and only leaves that are being impacted are the lower leaves.
The grow environment is detailed in my grow journal here.
The plants went in the res on 10/02/21 and I did not swap out the res after a week, due to work schedule and due to the fact that it’s a 35 gallon//28 usable res and there were just 4 seedlings in the res. Air pumps were running for the two week period. Over that two week period, pH rose from 5.9 to 6.0, then to 5.9 and, yesterday, 5.8. Water temps are maintained at 68°.
VPD was 0.8-0.9 with ambient temps ranging from 76° to 82°. LST’s have been about -1° from ambient.
Nutes are Botanicaire Kind Expert and the EC was 0.4. I swapped the res today and the new EC is 0.8. I realize that’s a significant jump but I’m not seeing issues with any other plants and this issue existed prior to the change in the res.
As a precautionary measure, I swapped out 7 gallons of nutes. EC is 0.62, pH rose to 6.1 after the addition of 7 gallons of RO water. I added two doses of 1 ml each Down. The pH fell to 5.9 and, after the second dose, 5.7.
I’ve checked some of the visual "sick plant” charts and, so far, nothing seems to match the symptoms that I’m seeing.
The rest of the plant looks great as do the other plants in the res. Roots are lengthy, well developed, and white. The res had very little residue in it and still had that “fresh res” smell that we all know and love.

Seeking the wisdom of the group - what’s the diagnosis and what steps should be taken to resolve the issue?

@Moony ? Can you help? You know I'm not a hydro person I don't want to misdiagnose

 

[garybo]

@Delps8 , before I give my opinion I want you to know I grow outdoor in soil, so my assumption is based on that experience.
My first thought was calcium def. Usually I've noticed the upper leaves the plant are effected first.

 

[Delps8]

@Delps8 , before I give my opinion I want you to know I grow outdoor in soil, so my assumption is based on that experience.
My first thought was calcium def. Usually I've noticed the upper leaves the plant are effected first.

I appreciate the caveat about hydro vs soil and indoor vs outdoor. Your plants must get huge growing outdoors - I'll have to check out your grow journals!

Ca (deficiency) - Starts dark in the center. Brown spots darken and spread. The common symptom in the plants is that the leaves are getting lighter, in splotches. And it's just to the two younger plants.

I've gone through each of the elements on this page and nothing quite fits the description of what I'm seeing.

Here are my notes:
Mutt (the top picture with the hygrometer in the image)
middle leaves
stems are a little red
light color between the veins
veins are normal color
Could be molybdenum?
Not Mo - Mo causes significant red coloration.

Jeff
Upper and middle leaves
Yellowing with some dark spots
Could be sulfur or iron?
Not iron - wrong spread pattern. What I'm seeing is leaves are getting light in patches and it's not starting at the stem.
Not sulfur - that starts at the base of the leaves and works its way toward the tips

 

[Moony]

@Moony ? Can you help? You know I'm not a hydro person I don't want to misdiagnose

There was a guy the other day who had something like this. Pretty sure @InTheShed knew what to do?

 

[Delps8]

Moony - thanks for brining that up. Should I PM him or does just putting his name in a posting send up the bat signal?

 

[bluter]

are you running cal-mag ?

 

[InTheShed]

Moony - thanks for brining that up. Should I PM him or does just putting his name in a posting send up the bat signal?

I'm not often here at night but then sometimes I am!

The DLI at 27 looks fine unless you're packing that into a shortened light schedule. I didn't see your lighting schedule, though I did see you used the same DLI chart as the one I posted in my DLI explainer here!

As gary and bluter mentioned, I'd want to know about the cal-mag (especially since you're on RO) since most of the rest seems like it ought to be fine.

[When you say Botanicare Kind Expert, is that the full lineup of 6 of the 7 nutes in their lineup? Just the 2 for veg?]

 

[Delps8]

are you running cal-mag ?

Yes. I thought I might have failed to include it when I made my batch of nutes but I checked my "feed sheet" and, as far as I can tell, CalMag was added in the required amount.

When I mix a batch of nutes, I first do a 4 gallon
at 100%. That gives me the TDS of the full strength mixture and I can use that to top off the res or bump the TDS. I just did that, in fact, raising the PPM from 310/500 to 370/500.

Per attachment, I use an Excel document to create a "Feed Sheet". My nutes are in water bottles in a carrier. Each nute is clearly labeled and, strange as it sounds, I call out the name on the bottle and check it against the feed sheet. I use a 30 gallon trash can to mix the nutes. Nutes are added using a large syringe and/or graduated plastic beakers. I wear a set of magnifier glasses to make it easier to read the syringe and nutes are added to the nearest 1 ml. As each nute is added to the trash can, I put a checkmark by the side of the nute and run my transfer pump to add a few gallons of water to the mixture in the trash can.

For this week, 100% strength was 850/500 and I wanted to hit 400 so I ended up with some unusual measurements. Hydroguard is italicized because it's 2 ml/gallon, regardless of the concentration of the nutes. CalMag does vary with nute strength since it's part of the chemical makeup of the nutrient solution.

 

[Delps8]

I'm not often here at night but then sometimes I am!

The DLI at 27 looks fine unless you're packing that into a shortened light schedule. I didn't see your lighting schedule, though I did see you used the same DLI chart as the one I posted in my DLI explainer here!

As gary and bluter mentioned, I'd want to know about the cal-mag (especially since you're on RO) since most of the rest seems like it ought to be fine.

[When you say Botanicare Kind Expert, is that the full lineup of 6 of the 7 nutes in their lineup? Just the 2 for veg?]

Heh, I'm glad you showed up tonight. I'm thankful for the help.

I just came upstairs from the tent and the issue continues, though it's confined to the middle and top leaves. I think there are two separate issues because the symptoms are different.

DLI of 27 - worst thing I did was by the Apogee (I kid). It's got a sample function so I'm now measuring PPFD at the rear, center, and front of each plant and using that as a "map". Before looking at the problem that way, I was using the highest PPFD reading as my number but, looking at how the values differ, I'm now going off of the average.

Lots of variance in just the width of a 3 week old autoflower. I'd never has guessed that.

My lighting schedule will be 24/0 today but has run 22, 21.5, and I've know I've done an 18/6. Definitely no intentional high intensity periods. When the first set of seedlings popped, I thought I might have gone overboard but, in retrospect, that was just my "helicopter plant daddy" kicking in. This is only my third grow - one in 2017 and one earlier this year.

I'm not really sold on that DLI chart. I snarfed a copy from the Photone site when I tested Korona/Photone. It's very different than the data from Bugbee and Chandra. I use data from the latter as my guide.

I was hoping it was CalMag but, per above, I'm just don't think that's the issue. I've got a lot of experience with SOP's so I'm pretty certain that CalMag made it in the mix. I had three gallons of 100% nutes leftover so I just now added them to the res to get the TDS to 370/500. It's highly doubtful that I've have failed to add CalMag to both my 100% batch and my 28 gallon batch so, if there's a CalMag issue there will be some, albeit a small amount, of CalMag from the 3 gallons I just added.

"[When you say Botanicare Kind Expert, is that the full lineup of 6 of the 7 nutes in their lineup? Just the 2 for veg?]" - it's the whole shebang. I ran that for the last grow and had zero issues. I had a lot of nutes left over so I just keep using them.

I just checked the water level tonight and there's water uptake and the Bluelab is flickering from 310/500 to 300/500. The water level dropped 1 cm over the course of today. That's only about a quart but these are very small plants. Looking at the WonderChart, the res is falling, TDS is sort of falling, and pH is static, so the res is, arguably, in good shape.

 

[Delps8]

Shed - I'm reading your tutorial on LST. Very, very helpful. Thank you for putting that together and posting it.

 

[InTheShed]

Glad you liked it!

The inter-vein degradation of the chlorophyll doesn't look like a calmag issue but it was a good place to start checking. And since you're feeding them cal-mag (and you seem to have your grow pretty well-controlled and documented!), I would next ask when the last time you calibrated your pH pen? I'm sure it was yesterday but I gotta ask.

Also, let me tag in my hydro guru @West Hippie and see if this is something he recognizes.

 

[West Hippie]

Do you have a pic of the roots ?
I moved to 4 mL a gallon calmag 1-0-0 but I’m in mc nutrients. RO water and leds call for more calmag.

 

[InTheShed]

Do you have a pic of the roots ?
I moved to 4 mL a gallon calmag 1-0-0 but I’m in mc nutrients. RO water and leds call for more calmag.

WH!

 

[Delps8]

Shed:

"I would next ask when the last time you calibrated your pH pen? I'm sure it was yesterday but I gotta ask."
Good question. I calibrated 10/05/21. Ssome of the lights on the Bluelab change when calibration is due but I did a calibration because that’s when I was setting up the res. I think the monitor was 0.1 low on the pH; the pen was spot on.
It’s worth calibrating again.

[time passes]

Pictures of roots and leaves on Jeff attached. The roots are from Winnie and Jeff, Jeff being the one most impacted.

 

[Delps8]

Do you have a pic of the roots ?
I moved to 4 mL a gallon calmag 1-0-0 but I’m in mc nutrients. RO water and leds call for more calmag.

Thanks for the suggestion. I’m at 2 ml/gallon - it’s worth a try to up the dose.

 

[West Hippie]

Whoa the slime is holding out nutrients, do you have Z7 or orca . I’d flush that off into an empty bucket .

 

[West Hippie]

Thanks for the suggestion. I’m at 2 ml/gallon - it’s worth a try to up the dose.

No wait let’s fix the roots first .