Need DEFINITIVE diagnosis. Small yellow spots on veins NOT mites...

Hi, been growing a little while now, and my latest grow is really pissing me off because my plants are showing symptoms which don't actually fit anything I've seen anywhere. Here are close-up Hi quality pictures of fingers from fan leaves taken from the MIDDLE of the plant. (though whatever this is has now finally spread to my fucking sugar leaves )

I have been flushing the plant these came from for a week now with a mix of carbon filtered and straight tap water (my tap water is 265ppm calcium and 0.14ppm fluoride, pH 7. which brings the average pH down to about 6.5 depending on the mix.)

The plant is a Chernobyl, and is in a potting soil/wormcasting mix with some blood, fish and bonemeal mixed in. I have a Skunk x Kush next to it which is much healthier though also has some of these spots if I look very closely.

I think it must be a pH problem, though I don't tend to use much feed anyway, so that shouldn't be the case. Either that, or it is a fungus or disease. I've looked closely at leaf rust spot symptoms, but as usual, the internet is clogged up with so many photos with incorrect labels that none can be relied on.

You can see below how the problem progresses, since I've picked leaves which show the various stages i.e. the top leaf looked like the one below it about a week ago.

I can confirm there are NO mites in my grow. I have checked and re-checked....

Notice how the chlorosis starts from spot mainly located on the veins....ruling out deficiencies which leave your veins green etc.

Some extra closeup shots...

Calcium deficiency?not definitive but I've seen that before.

Did you mix in some lime and Epsom salts? If not I would say a fluctuation of PH mixed with an MG def...or a salinity build up causing a nute lockout, which according to the last pic, that's what it looks like IMO...good luck

Hmm...I bought a big bag of epsom salt last year, and have tried using it (sparingly)....one question I do have. Is there any easy way I can check that it is epsom salt, rather than...say....normal salt. (is epsom salt safe to taste, and what would it taste like?)

The soil mix should already have lime in it, since it was based on commercial potting soil. Annoyingly though they never bother to mention this on most bags you get from the garden centre. Maybe I need to add more given the wormcasting additive. Are wormcastings quite strongly acidic? I always thought using neutral pH water with limescale in it would help offset any acidifying effects in the soil. (my pH pen is fucked, so I can't check run-off now...but as I said...I flushed anyway, so the soil should now be neutralised shouldn't it??

I figured calcium was possible early on, but given my water is pretty hard the only way that can (I guess?) be locked out is pH or salt problems, which the flushing should have taken care of!! Unfortunately the problems don't seem to be stopping (though it's hard to tell really since the damage had already spread pretty far). Isn't it a bit strange to see calcium def on it's own with a pH/salt problem?? I dunno enough about it myself..

One other major detail I left out was that the shaded leaves are generally all fine and perfect. Only leaves (and parts of leaves) which are in direct light are noticeably affected. The leaves in the photos above however were not "too close" to the lights. They were all about 1ft away. My room temp is 23C (73F) day and 20C nights. I have an 5" RKV running full blast to extract air, and two small fans in the tent to keep air moving (though they all switch off for 5 hours or so overnight).

How well did you mix your medium when you added the amendments? And how long did yo allow it to cook before planting in it? Looks like nute burn too me. Due to poorly mixed medium that was planted in before it was allowed to properly compost.
You mentioned limescale. Limescale is compromised of calcified lime which is a horrible thing for your medium. Get that in your medium and your basically fucked. As there is no effective way of removing it.

Hmmm...That may be the case, since although the wormcasting were added to the basic soil well before I planted them the blood, fish and bonemeal was added at the last mix, just before re-potting. I didn't think organics like BF&B were likely to burn my (fairly mature) plants though tbh?

I do have limescale, but it's not so bad that my kettle is forever furry. There's limescale in almost everyone's water around here, so I'm not sure how it is not affecting them too if it's a problem. I have a friend who does hydro using the same tap water with no issues. Given I'm using a peat-based medium I've always assumed that any pH problems I might have would be caused by excess acid rather than limescale. I'm no chemist though...does acid not dissolve limescale allowing it to be flushed out?

MajorCoco said:

Hmmm...That may be the case, since although the wormcasting were added to the basic soil well before I planted them the blood, fish and bonemeal was added at the last mix, just before re-potting. I didn't think organics like BF&B were likely to burn my (fairly mature) plants though tbh?

I do have limescale, but it's not so bad that my kettle is forever furry. There's limescale in almost everyone's water around here, so I'm not sure how it is not affecting them too if it's a problem. I have a friend who does hydro using the same tap water with no issues. Given I'm using a peat-based medium I've always assumed that any pH problems I might have would be caused by excess acid rather than limescale. I'm no chemist though...does acid not dissolve limescale allowing it to be flushed out?

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Your mix not properly composted burned your plants. I am pretty sure thats your problem. Just ride it out and monitor new growth. They should recover ok. Worm casting can be added anytime though with no issues.
I have hard well water also, 275-300 ppm with 160ppm of it calcium and it grows great. Its not the dissolved calcium thats a problem. Its once it precipitates out of solution and become scale thats a problem. Never try to re dissolve this scale and use it on your plants, bad news. Also never use water from the hot tap as it to can contain calcified lime, again bad news.

MajorCoco said:

Hmm...I bought a big bag of epsom salt last year, and have tried using it (sparingly)....one question I do have. Is there any easy way I can check that it is epsom salt, rather than...say....normal salt. (is epsom salt safe to taste, and what would it taste like?)

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lol...It will say "Epsom salts" on it, and yes it's safe to taste, it's an old school remedy for diarrhea..lmao...so don't taste much.. I mix a couple of quart size cartons into my soil with the dolomite lime...View attachment 2717656

And ya what supertramp said, you have to let that soil mix set for awhile,(I let mine set for a month) and stir it up daily...good luck.. here check this out... https://www.rollitup.org/organics/539844-subs-supersoil.html

Cheers! Ha...if the bag had anything written on it I wouldn't be suspicious. I got a cheap bulk bag of epsom salts off amazon, so it doesn't have flashy packing with like, words on and stuff That'd obviously be way too expensive! I'll give it a quick taste this evening, but may also head to the chemist to buy a little box of the proper stuff to compare.

Not that it really matters, I haven't fed for a week now, nothing but water and a tiny bit of organic kelp juice...and they don't seem to be suffering any worse than before. Although I reckon my chernobyl's harvest will be down by 25% at least on what it should be because this all kicked off just when she was supposed to be sending out most new buds. Shame, cos it's loaded with crystals....still. Only a couple of weeks left till harvest now...