Weird discoloration on one of my plants

Running Sohum soil in a 2.5'x2.5' tent with two Viparspectra V300's for light. I water with tap, chlorine evaporated, pH'd to 6-7, whenever the pots feel light and / or the cheap moisture meter I got reads Dry.

The plant this happened to is a Gelato Cake pheno from elev8 seeds, though I don't think it has anything to do with genetics. I had similar discoloration in both plants on my first run.

The affected plant is noticeably smaller than the others, it's the lady on the far left:



Here's a closeup of the discoloration:



Like I said, I had a similar issue in my first run, pics are in the grow journal if you think the info there would be helpful. I thought it was due to my crazy basic (8.5+) water, but now I'm not sure at all what's going on.

Any ideas what could cause this discoloration on just one plant in a generation that are all getting the same treatment?

Light burn m8

What's the hottest it gets in the tent?

Negrodamus said:

What's the hottest it gets in the tent?

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That's my veg tent, which I run open. The max on my thermometer is 83 F, I can't recall when I last dumped the memory on it. I usually never see it above 80 in there.

SmoknKush420 said:

Light burn m8

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Missed this somehow yesterday.

Light burn seems unlikely in this case, the plant in question is shorter than the rest of my plants, which are not suffering from the same. Also it's on the lower leaves rather than the upper ones, new growth is still seeming fine. I have these lower powered LED's hanging about 18-20" above the tallest plants in my canopy.

I’ll guess nutrient lockout related to ph. There’s a big difference between 6 and 7 ph. Try mixing the fert adjusting to 6.5 and the check in It after 24 hours. As an alternative you could use distilled water or water collected from a dehumidifier. That should start off at 6.7 and very little alkalinity so the ph can be moved easily.

Looks like a magnesium deficiency to me

Hit her with some calmag

Rdickenson said:

Hit her with some calmag

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He’s using tap water starting at ph +8.5. I don’t it’s a lack of cal mag.

Merlin1147 said:

I’ll guess nutrient lockout related to ph. There’s a big difference between 6 and 7 ph. Try mixing the fert adjusting to 6.5 and the check in It after 24 hours. As an alternative you could use distilled water or water collected from a dehumidifier. That should start off at 6.7 and very little alkalinity so the ph can be moved easily.

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Could be, that was my initial thinking when it happened to my first couple plants. It's why I started pH'ing in the first place. It's weird that it only happened to one plant here, though.

I generally shoot for 6.5-6.8, but if it's 7 or 6.3 I don't mess with the pH solution any more. I don't even have any pH up solution. I'm growing in Sohum soil, the bag says best results at 6-7 pH, their website says between 6 and 6.5.

This last watering I hit them with 6.0 pH water, after a few higher pH waterings (6.5-7). If that's the issue then hopefully I won't see any more discoloration.

You still may want to check the solution after 24 hours to see if there is any bounce back up once it stabilizes and readjust it.

I could be wrong,but that doesn't look like lockout to me
I just treated a plant with the exact discoloration with calmag,fixed it right up

Merlin1147 said:

You still may want to check the solution after 24 hours to see if there is any bounce back up once it stabilizes and readjust it.

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So my basic technique right now is just to pH my reservoir shortly before I need to water my plants. I have checked my reservoir a day or two after and it always creeps back up to some degree, but I haven't tried correcting it over days to see if I can get it to stabilize.

Have I just been doing it wrong? I suppose that could be causing issues for me.

Rdickenson said:

I could be wrong,but that doesn't look like lockout to me
I just treated a plant with the exact discoloration with calmag,fixed it right up

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It very well could be, but I'm cautious about adding nutrients. I grow in super soil, and only amend a bit at the end of flower to help my girls fatten up as the soil uses up its nutrient contents.

Difference reasons for the same problem. A lack of calmag in the fertilizer solution is only one way plant will exhibit deficiency. Most often though there’s plenty in there especially with tap water but it’s getting lockout. You see it a lot will high use of K which is antagonistic to cal mag. Typically 3 weeks into flower.

RadicalRoss said:

It very well could be, but I'm cautious about adding nutrients. I grow in super soil, and only amend a bit at the end of flower to help my girls fatten up as the soil uses up its nutrient contents.

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I understand what you are saying...a quick solution would be to flush with ph 6 water and feed again,add some calmag

I didny read the thread look up deficiency I'm pretty sure that one Is cut and dry very obvious signs. Can remember exactly what it was but look on Google for def and u will find it fast