Dark spots on Blue Dream Plants

[stevertr]

Hey all,

Need a bit of help on this one. I've searched all the forums and photos I can find, and I'm just not seeing anything that is a good match for my problem.

Early last month, when I first spotted the issue (pun intended,) I thought it might be a Mag deficiency. I switched from a basic one-part fertilizer and no supplements, to a full feeding and supplement regimen, the General Hydroponics system, including the three part fert., (Floral Grow, Bloom and Micro, Cal-Mag, Diamond Nectar, Liquid CoolBloom, and Floralicious.

Again, this issue predates the addition of all the items above, so it was neither caused by any of them, nor has it been solved by using them.

The plants are under normal growing conditions, lights, temp, Ph, RH, ventilation, all in spec. There is no correlation between it appearing on an upper vs lower leaf, nor a correlation between old leaves and new. It is not affecting all the leaves. On one large plant today, I just picked off about a dozen affected leaves. There is no correlation between adjacent leaves either...it's one of here, another one way over there, one down on the bottom, one on top on the other side, etc.

It is currently on three of my six blue dream plants, but not spreading at all to any of my other strains, all of which are in the same grow tent.

Sorry to ramble, but I thought that the more detail I could provide, the better.

I'm attaching a few photos, in the hopes that someone has an idea or two.

Many thanks in advance.

[Karsa]

What are you growing in?

[Karsa]

Could be boron, calcium or magnesium deficiency. If you've upped the cal-mag then I would say boron

[stevertr]

Could be boron, calcium or magnesium deficiency. If you've upped the cal-mag then I would say boron

Thanks so much for the feedback.

I'm growing these in soil.

I don't believe that its a Boron issue, since the Floralicious supplement contains Boron. I'm also using Cal-Mag, so I know it's not that either.
Additionally, I have six Blue Dream plants and 6 of another strain.
All are on the same regimen and under the same conditions, but these spots are only affecting a couple of the Blue Dream plants. If it were a nutrient issue, one would expect it to affect them all...or at least all of the Blue Dream plants.

Oh here's another tidbit. These spots appear quickly. I didn't see any spots this morning, and this evening I piucked off over a dozen spotted leaves.

Any ideas would be so welcome.

[Karsa]

Just so you know it's 10 plants max on this forum....

[kbag]

looks very similar to black spot to you get on roses.

[stevertr]

Just so you know it's 10 plants max on this forum....

Thanks for letting me know that. I'll edit my comment. Here in Mass, 12 is the legal number. I'll fix it now if it allows me to edit the post.

[kbag]

If i was you Steve i would remove all affected leaves and up the temps. Do not drop the r/h as this will make it spread just up the temps and improve the airflow.

[stevertr]

If i was you Steve i would remove all affected leaves and up the temps. Do not drop the r/h as this will make it spread just up the temps and improve the airflow.

Thanks for the suggestion. I really appreciate it.

I have removed all affected leaves, but others pop up a few days later.
Note that all temps and other parameters are in spec, and that this issue has been occurring for a month, with temps bouncing off the mid 80's.
Additionally, as I mentioned, I have six Blue Dream plants, all together, and thus under the same parameters, and these spotted leaves are only occurring on two of them.
I'm speculating that if it was environmental, either due to growing parameters, temp, RH, etc., it would be appearing on all six plants.

My guess, therefore, is that it's either a pest of some kind, or fungal in nature, but I can't find any pics that seem similar.

[kbag]

Black spot is fungal that is why i suggested upping the temps. do you rotate your plants? Maybe a cool spot in the groom? have to ask these questions