Help - One of Four Plants Yellowing Fast and Maturing Slowly

[growchick]

I planted four plants at the same time (same strain). Autoflowering Narcotherapy - the fourth plant is really behind in development (although it's the tallest one). It looks a month younger than the others. Now, it's starting to yellow very badly. The large fan leaves are all going pale, which I would expect if it were going to be picked this weekend like its seedmates, but there's no way it will be ready for harvest any time soon.

See more detail/pictures in my grow journal



pH is a little low - hovering around 5.0. No clue why it is so low - it was holding very consistently between 5.85 and 6.0 for the last several weeks. It dove down under 5 early last week. I've been struggling to get it up ever since.

Is something in the plants causing the pH drop? Is the pH drop causing the yellowing? Is something else causing it? Why just this one plant (they all share water)?

 

[growchick]

Anyone got any ideas? It's getting worse.

 

[maureensmith]

This looks like nitrogen deficiency. First thing I'd check is pH to make sure it's not locked out. But that looks very much like low N.


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[Rifleman]

Get your ph up. I fight to keep it down all through veg, then when it comes to flowering it wants to dive.

 

[Emilya Green]

check your roots for damage too... decaying roots can affect pH and present as an N deficiency.

 

[growchick]

check your roots for damage too... decaying roots can affect pH and present as an N deficiency.

Thank you. I did check the roots - they are white and quite healthy. I didn't think to check them at first but when I was panicking again last night, finally thought to do so. hehe

Get your ph up. I fight to keep it down all through veg, then when it comes to flowering it wants to dive.

The pH is back over 6 now (more over than I'd like). I just don't understand why it took the dive under 5 after all the struggle to keep it under 6 in the months before.

Nitrogen lockout bc of low pH is what I finally came to this morning. I don't know why I didn't just think about it properly before - I was really in a panic, I guess.

I mixed up nutes and fed them - the PPM was down under 700 this morning. I am guessing the pH up I added finally kicked in and they were able to start taking up food again so the PPM plummeted. I hate to feed this close to a harvest, but I also want this little one to make it TO the harvest.

Here's some shots of the plant this morning just in case this thread helps someone else in the future:

 

[MRXC]

Maybe this could help you with the ph

 

[DEAN420]

Yep that's N def for sure, when did you switch to flowering nutrients?

 

[growchick]

Yep that's N def for sure, when did you switch to flowering nutrients?

I just spent the last 5 minutes staring at that insect in your avatar.

I switched them several weeks back. If all the plants had done this, I would have thought N def instantly, but it was just one of four, so I was confused.

I fed them a good bit today.

 

[mokel]

perhaps this plant is a bit gluttonous compared to the rest of the pack

 

[DEAN420]

I just spent the last 5 minutes staring at that insect in your avatar.

I switched them several weeks back. If all the plants had done this, I would have thought N def instantly, but it was just one of four, so I was confused.

I fed them a good bit today.

Doesn't matter some plants have different needs, either up your feed a lil or give the plant what it wants, some more veg nutes or something high in N to rectify what's been done and get that plant back on track