Stem Rot?

I have 4 plants, 2 sterile n 2 with bennies in top fed dwc w air stones n temps below 75. Closer to 65 now. Their stems are all developing this kind of brown stringy surface, for some reason I thought it was just trying to make roots higher up (high ass) I have been spraying them with h202 either way, and I gave my bennie plants extra myco today.

I thought I was feeding wrong but I feel I may just have and underlying case of that rhino root rot bacteria. Roots seem okay, nothing slimy and what discoloration there is, is uniform.

It's week 4 of veg (I think they are growing quite slow for dwc, barely 12" in height as stretching was kept down) and my ppms are around 500 total in sterile, 600 in bennie tank. Both ~5.8pH. As well as main stalk issues, leaves seem to have been hurting from nutrient excess. I have some form of white powder that consistently builds up on my hydroton, I am using mineral based nutrients so could this be salt buildup or a form of mildew? Pics attached, appreciate any feedback!





Sidenote, my plant with bennies is definitely doing better than the same strain in sterile.

Have you measured the ec of the run off?

How high you running the water level in the reservoir? That's salt buildup on the hydroton. And the second pic of the leaf ;hard to tell if some kind of leaf residue, or possible thrips. But, roots look healthy from this angle; so that's a good sign at least.

pH is steady 5.8

Star Dog said:

Have you measured the ec of the run off?

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don't have to adjust much between fills and if I do it's only ever ph down.

ktmracer51 said:

How high you running the water level in the reservoir? That's salt buildup on the hydroton. And the second pic of the leaf ;hard to tell if some kind of leaf residue, or possible thrips. But, roots look healthy from this angle; so that's a good sign at least.

Click to expand...

My water is a little higher than necessary, around 12gal in a 20gal tote with 2x6" net pots. Leafs have gotten bronze spots randomly and seemed to recover from a defoliation & fimming. But older growths have been quite bronzed, had possible WPM at first so I spray with h202 or neem every morning. I think this rot has caused my nutrient lockout/deficiency problems, as they even have holes in some leaves with no sign of thrips or pests whatsoever. I believe my daily h202 spray has kept rot at bay as well (use hydroguard n myco in bennie tank, h202 + sodium hypochlorite pool shock in sterile)

I feel I should just kill em, at the best take clones for outdoor.

that 4th pick are exactly what mine looked liked... i had water running on the stem, i adjusted the water lower and most recoverd.. you might have to stake them up for a but, there is a good chance they will come out of it if you can fix it in time. ill try and find the pick i posted.

found it the pic quality is crap but you can see the weak spot..https://www.rollitup.org/t/a-weak-spot-in-stem.1005319/#post-15296627

mine any began falling over, so you should beable to save em in time... just make sure no water is flowing at the stem. best of luck

ktmracer51 said:

How high you running the water level in the reservoir? That's salt buildup on the hydroton. And the second pic of the leaf ;hard to tell if some kind of leaf residue, or possible thrips. But, roots look healthy from this angle; so that's a good sign at least.

Click to expand...

Was thinking the same thing about thrips. I dont see any frass left behind. With that extensive of damage surely they would leave some poop.

The only time i had thrips what tipped me off was the excrement. I noticed the damage secondary.

Ok, it was late last night but, I've put some more thought into this a little bit. I have a hort degree and have worked years commercially but still take this for what its worth....an opinion. I have tons of past experience with diseases and viruses and sometimes it cut and dry with the problem but, ultimately a lot of times is an educated guess. And the only way to truly be sure of the issue is to send off samples to a lab or have good quality lab microscopes and the knowledge to diagnose it. Anyways, look into Fusarium stem canker. There are multiple types of Fusarium so a bit tough to pinpoint it exactly but, that's a culprit I'm leaning on. Hopefully that helps in the right direction.


Also: you noted the lower leaves bronzing. Also a sign of Fusarium.

oregonhydro said:

pH is steady 5.8


don't have to adjust much between fills and if I do it's only ever ph down.



My water is a little higher than necessary, around 12gal in a 20gal tote with 2x6" net pots. Leafs have gotten bronze spots randomly and seemed to recover from a defoliation & fimming. But older growths have been quite bronzed, had possible WPM at first so I spray with h202 or neem every morning. I think this rot has caused my nutrient lockout/deficiency problems, as they even have holes in some leaves with no sign of thrips or pests whatsoever. I believe my daily h202 spray has kept rot at bay as well (use hydroguard n myco in bennie tank, h202 + sodium hypochlorite pool shock in sterile)

I feel I should just kill em, at the best take clones for outdoor.

Click to expand...

That’s the ph not the ec/nutrient strength, what tds/cf/ec is your feed?

Star Dog said:

That’s the ph not the ec/nutrient strength, what tds/cf/ec is your feed?

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My feed was around 450ppm did a side by side sterile and bennies grow. Sterile did better, beautiful roots but sterile was hurt by the stalk rot faster. Had to kill these plants before I wasted too much time on them

ktmracer51 said:

Ok, it was late last night but, I've put some more thought into this a little bit. I have a hort degree and have worked years commercially but still take this for what its worth....an opinion. I have tons of past experience with diseases and viruses and sometimes it cut and dry with the problem but, ultimately a lot of times is an educated guess. And the only way to truly be sure of the issue is to send off samples to a lab or have good quality lab microscopes and the knowledge to diagnose it. Anyways, look into Fusarium stem canker. There are multiple types of Fusarium so a bit tough to pinpoint it exactly but, that's a culprit I'm leaning on. Hopefully that helps in the right direction.


Also: you noted the lower leaves bronzing. Also a sign of Fusarium.

Click to expand...

Thank you, I think this is basically what happened, as in at least a very similar disease to this one. I'm surprised I can't find pictures anywhere quite similar to mine. I didn't have any tar I'd seen people use to cure it so I've restarted with clones, new buckets new lining new everything completely sanitized room multiple times and outside of room before, and yet I am still battling what seems to be similar.

It may have come with the clones I got, the only other disease I think it could be is grey mold/bud rot, in it's trying-to-enter-the-plant form. I am doing all beneficial bacteria this time and will try to use hydroguard to fight it, directly applying it.
Btw, ppm is around 400, temp 68-78, rh was around 40 but keeping it around 20 now to combat this.

This is how they look now :