What caused this leaf damage?

Hey everyone, I noticed some funny looking dark spots on a few of the older/oldest leafs on some of my plants. The spots later turned brown and the leafs became brittle. Here is a picture of a few fan leaves I cut off three of my plants.




I've looked through the section of the grow FAQ about plant problems but I haven't been able to figure it out. This is from my first grow, the journal of which is here.

I would greatly apprciate any advice or suggestions anyone would have to offer.

if theres not bugs, then deffo, over feeding or old soil.
how far on with your grow are you,
i only start feeding when i get to 12/12, then only every other water.
any pics of your full plants?.

I haven't been able to spot any bugs, but I did up the nute concentration of my DWC recently. Here is a pic of the full plants.



You can see a little bit of the leaf damage I'm talking about on the plant in the front, on the left. You can see I began LSTing them a few days ago.


If it is over feeding, how do I remedy that? Do I just change the reservoir of my DWC to a lower concentraion of nutes and thats it? Or is there anything else I should be doing to help the healing along?

Does anyone else have an opinion about what they think the problem might be? Do these leafs look like hydroponic nute burn? Or are they something else?

Hi Mate, could it be that you damaged some roots when you tied them back? It almost looks on these picks that your stem didn't really bend much on the plants that seem to be the most stressed? Are you careful not to get any nute solution directly on to your leafs?
I wouldn't bend them much more until they look better!

Having said that, I'm a noob, take my diagnosis with the proper caution!

Good luck Mate,
Unity

the lite looks too far away. how old are the plants and what lite sced are you on?.

also have you got a fan to make the stems stronger.
if i was you id hold them up with somthing, and goto soil till i cud grow better, but if not, just stalk them up get a fan, stop feeding so much and get the lite closer. have a fan blowing inbertween the lite and top of the plants.
plants need flowing air.
what lite are you using?.

on having a closer look the plants look fine, dont pull any more leaves off and stake them up, i dont know about hydro, but couldnt you bury the stalks so the plants can stand up.

crazy-mental said:

on having a closer look the plants look fine, dont pull any more leaves off and stake them up, i dont know about hydro, but couldnt you bury the stalks so the plants can stand up.

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Hey Crazy, i think he states that he bend them over on purpose, but the stems look like they didn't flex enough.

why did you bend them there only tiny, and not even fighting for lite, there still babies. did you pull all the bottom branches off?.

looks like your giving it to much nutes, or either pest

I just upped the nutes a few days ago and then this issue manifested itself. If people think that nute burn could be it, I think I agree.

Also, crazy mental, I'm LSTing my plants. I'm basing my technique on this post. That post said that you could begin LST when the plant had 3 or 4 sets of leafs, which my plants had. So I bent them over and held them in place with twist ties and tape. The plants seem to be responding well to the training. But I'm just a beginner, if it looks like I'm doing something way off, let me know.