Yellow leaves week 9 autoflower


Have been feeding half dosage of the Fox farm nutrient trio with cal mag. Just fed yesterday. Ph has been around 6.2 for feed and 6.6 runoff. Last ppm runoff I checked was around 900 runoff.

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Can you give us more info such as strain, lighting, environment, any and all you can will help. I’m afraid it favors septoria, and I sure hope it’s not!

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Welcome to the forum! You’re in the right place, they’ll get ya fixed up.

2 things stand out to me.

A
Have you calibrated your pH pen with the three pH calibration?

Your pH in your feed at 6.2 and running off 6.6 this sounds like salt buildup or non calibrated pen

B
Have you done a fox farm trio maintenance flush? Not following their recommended flushing maintenance will create salt buildup in the soil and root zones and restrict proper nutrient uptake. (Classic look of your leaves currently)

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Although Septoria leaves will take on the coloration of yellow/light green, his leaves are missing one aspect if it were indeed septoria and that’s the rust colored spots
That always show up early in the yellowing area. (See infected image below)

I battled septoria in the outdoor garden and it’s nasty and if not caught and treated will destroy your plant quickly. I just don’t see the rust anywhere in the leaves that he’s posted. Nevertheless, it does look like it minus the rust spots so good call

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It’s northern lights auto. Running 20-4 lights steady 74 with lights on and 69 off. Humidity like 35%

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Those number of ph might not be 100% I can’t remember and didn’t write it down each time. But my ppm was low so i didn’t think buildup. I haven’t calibrated the pen in a month so I’ll do that and get an accurate run off next water. I haven’t flushed mainly bec Of the runoff ppm being low and because I didn’t start feeding until Wk4

Your relative humidity is to low. In flower I would bring it up to at least 50% - 55%

Regardless of your ppms, flushing Fox farm trio seems to be a crucial step that many people fail to do and suffer the consequences. Fox farm nutrients are one of the saltiest on the market hence the reason they tell you the flush

If you started feeding in week 4 and you were now in week 9 Fox farm recommends every 30 days if I’m not mistaken. You’re overdue.

Your runoff PPM at 900 is it okay. You want to bring it up to 1000ppm and try to stay as close to it as you can with 6.5 pH on the runoff as well.

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Besides the fact that I am due for a flush. Would a salt build up cause this much yellowing. is there a deficiency going on as well.

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So with a flush. Because it washes away everything I assume I have to feed with nutrients right away right.

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It all sincerity, it looks like magnesium deficient. Generally not caused by the lack of magnesium but the lack of available uptake of magnesium due to a pH in balance.

What would I do if this were my personal plant

A I would calibrate my pH pen
Eliminating any potential issue

B I would follow the recommended flushing procedure that Fox farm instructions you. Ph’ed to 6.5 (document intake and runoff numbers both PPM and pH)

C after flushing I would come behind with a gallon of half strength fox farm adding 100 PPM of magnesium to the feed by way of Epsom salt unflavored unscented. Ph’ed to 6.5
(Document intake and runoff numbers both PPM and pH)

Keep in mind these are my opinions. There’s a lot of people in this forum. Feel free to investigate others opinions as well. Then go with your gut

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I actually have epsom salts on the way via Amazon lol. I’ll first start with the pen and go from there with the rest. Some people on a discord group said some similar things as well. Thanks for the information

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The pH of the runoff I get from the virgin Ocean Farm I’m using presently is always 7.0 ± 0.1, even though I always adjust whatever I’m pouring on the plants to 6.5 as the final step.

The only time I’ve gotten 6.5 in my runoff was during an experiment. I kept pouring water I’d pHd to < 6.5 in and measuring the runoff. Reducing the water to 5.8 finally gave me 6.5 out.

The next time I measured the runoff from that pot, 6.5 in gave me 7.0 out, as usual.

I use a Bluelab Soil Pen and calibrate its 4.0 and 7.0 readings when the pen tells me to, i.e., every 30 days.

PS - Did you notice he’s been feeding the FF nutes at half-strength? Don’t know whether he’s watering enough to get 20% back as runoff.

I have the same issue going on same week Zkittlez Auto

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Welcome to ILGM @Austin127 and @OutlawGrower92 .

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Welcome to the forum @Austin127
Welcome to the forum @OutlawGrower92
No thats different. Austin127’s is intervienal (between viens) yellowing on mid and newer growth.
Outlaw92 you got overall yellowing. In flower, probably hungry. More 8nfo about your plant and we’ll know.
New members are limited. Soon yiu can start your own topic/thread or grow journal.

Did everything suggested. All ph is right. Plant seems


to be alright minus the discoloration.

Good job. Keep in mind leaves yellowing are not going to fix themselves. They will not restore to vivid green. However, don’t cut them off let them get all the resources out of the leaves that they can. They’ll eventually Brown and fall off.

Keep feeding to get a liberal runoff of 20% (very important with FF trio)

Try to Maintain a 6.5ph and 1000ppm runoff each time you feed

Keep track and do your FF maintenance flushes as recommended by your feed chart.

Keep your environment dialed in with heat and relative humidity

You shouldn’t need any more Epsom salt feeds. For the record, I personally like to use epsom salt 2 times per grow on an auto flowers. I normally do a small shot 100ppm in week 3 of veg and another medium shot 150ppm in week 4 of flower and I never see magnesium deficient leaves.

Keep your watering practices in check. Always allow that one day of dry time for oxygen uptake.

You’ll be just fine. I wish you all the best. Let me know if I can assist

If im feeding half dose and flushing is that much runoff really needed .

Also. Is there a good was to tell the difference between nutrient lockout and nutrient deficiency? Another one of my plants is starting to show some discoloration