Mystery Spots: Please Help Identify!

M

MisterWhilom

Active Member
I have some Kali Mist seedlings — about 3 weeks old — in my DWC cloner, and they've started developing some markings that I've not been able to reliably cross-reference by looking at pictures of diseased leaves.

Here's one plant, first a wide shot and two tight:
Image00001.jpg Image00002.jpg Image00003.jpg

Here's its neighbour:
Image00004.jpg Image00005.jpg Image00006.jpg

The burn on the second plant looks like a toxicity of some sort, but the white speckling is a mystery to me. Toxicity? Deficiency?

Data on the environment and gear:

Air temperatures: 76-88F daytime; 71-76F nighttime (active cooling is my next planned upgrade)
Relative Humidity: 27-55%; I have a humidifier to help on the dry days
Cloner: 20L, 13-site DWC
Lighting: T8, 60cm; 4 × 18W; Magnetic ballasts
Water temperature: ~76° - 80°
Water: Reverse Osmosis; 72-80 µS[SUP]1[/SUP] (740-ish µS at the tap)
Reservoir EC: ~500µS
Nutrients: FloraMicro/Bloom using Lucas Formula; RootJuice
pH: Stable, 5.5 - 6.2

I'm'a change my res water and see if the problem clears up, but I hope that in the meantime one of the leaf-reading gurus here will be able to diagnose the problem.

Thanks for reading!


MW

notes:
1. Corrected to "µS" from "ppm"
 
Dr Kynes

Dr Kynes

Well-Known Member
why you using a flowerin nutrient mix on those lil plants? give them more nitrogen and less phosphorous and potassium. if them was tomatoes i would say its potassium burn, and nitrogen deficiency. untill they start budding or fruiting, too much p and k can hurt your plants. clear yur reservoir, and refill with a 1/2 str mix of veg nutrients with micro nutrients and see if they dont set better growth. that one really badly burnt leaf should be removed.
 
M

MisterWhilom

Active Member
Dr Kynes said:
why you using a flowerin nutrient mix on those lil plants?
Click to expand...
Good point!

My understanding is that the Lucas formula is a full-cycle nutrient, and accounts for the nitrogen balance in the solution.
I'd figured that with a low EC (~550 µS) I might encounter some deficiencies but I didn't think I'd burn anything.

Shows what I know.

I'm gonna try reducing the ratio of FloraBloom to FloraMicro.

I clipped the burned leaves right after I snapped those photos.


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M

MisterWhilom

Active Member
Coho said:
RO water..do you add calmag+?
Click to expand...
Where I live we have, if anything, an excess of minerals in our tap water.
My best-case RO scenario is a reduction from ~740 µS[SUP]1[/SUP] to 72 µS[SUP]1[/SUP], of which the remaining parts are (judging by the buildup in my kettle) primarily calcium.
I take that 72 µS[SUP]1 [/SUP]into account when I calculate my EC.


notes:
1. Corrected from "ppm" to "µS"
 
lahadaextranjera

lahadaextranjera

Well-Known Member
Yes but I think u need 100 ppm min of Ca. I add EC 0.1 of Ca and also Mg EC 0.1 to buffer mine OR I use tap water to EC 0.2.

Ferts are designed for tap water users and have some Mg and Ca in them.
 
M

MisterWhilom

Active Member
lahadaextranjera said:
Yes but I think u need 100 ppm min of Ca. I add EC 0.1 of Ca and also Mg EC 0.1 to buffer mine OR I use tap water to EC 0.2.

Ferts are designed for tap water users and have some Mg and Ca in them.
Click to expand...

True, I'll mess with adding some tap water back into the solution to get my Ca & Mg.
Where did you get the 100 ppm figure?


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crazyhazey

crazyhazey

Well-Known Member
MisterWhilom said:
I apply a neem oil solution regularly and inspect just as frequently.
I'd be surprised if any pests got through.

Good thought, though.
Click to expand...
then id probably say cal/mag like a few others did state, this is the early stages but it usually looks like these spots.
 
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