Nutrient problems - need help Diagnosing problem

I am not sure what the problem is and I’m having a hard time figuring it out. I Have a 4x8 indoor grow in 5 gallon pots with organic soil. The temperature stays right around 75 to 79° and humidity stays somewhere around 50 to 60. The plants are about midway through their fifth week of flowering. Leaves on a few of my plants are yellowing and starting and dying off. One plant is starting to develop little rust colored dots on the leaves. I thought this was a nitrogen deficiency so I increased my feeding schedule and upped the nitrogen. The plants seem to respond and yellowing reduced. Now it seems to be reverting back to yellow and now there are dots appearing. I’m not sure what the problem is any help would be greatly appreciated. Thanks

Strain; girl Scout cookie extreme, and Bruce Banner. Grown from Feminized seed

Soil in pots, natures care organic

System type? An

PH of runoff or solution in reservoir? Na

What is strength of nutrient mix? EC, or TDS
Not sure I’m using advanced nutrients.

Indoor gro

Light system, size? 400w HPS

Temps; Day, 75-79 Night 65-70

Humidity; Day, 50-65 Night 50-80

Ventilation system; Yes, 6” Exhaust fan keeping the tent under negative pressure

AC &, De-humidifier Running outside of tent

Co2; No

Gunna need some pics under normal light to really see what’s going on.

I’m starting to think it’s a potassium problem

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Are you using a cal/mag supplement ? Looks like a mag deficiency to me


I am not. I was under the impression that my base nutrients had enough in it. I will add it to my feeding schedule and see what happens. Thanks

What week flower are you In?

Just over 4 weeks

Some of my other plants are bigger and farther along than these two

So your feeding at .51fl oz of A&B? And watering till run off?

What kind of water are you using? Well, municiple, R/O, distilled?

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I should mention that this is my first grow. So I still have a lot to learn. Nutrients have been a problem for me thus far. I posted a picture of the nutrient schedule that I am following. I have made a few changes from week to week but for the most part this is the dosage I am following. I am also mixing in 4 mL of mother Earth per gallon at the moment. I’m feeding a little over a liter of this mixture to each plant every other day. About a week ago all the leaves turned yellow. So I upped the nitrogen and feeding. The plants recovered for a bit and then took a turn to what I have now. I am using well water with a PH of 5.7- 6

If your only feeding at 15ml of A&B per gallon it’s probably not enough for that strain. That’s why you
May be running into deficiencies . It should be around 30 ml or 1/2oz of A&B bloom. I use the bud labs app from advanced nutrients

Get yourself a good TDS meter and measure your run off. That is probably the best way to determine how much nutrients they are consuming.

I’m not using the sensi bloom A&B. My base nutrients are the perfect pH micro, Bloom,& grow. I’m guessing I will need to do some more research and add a few more nutrients to my bag.

These nutrients?

This is AN suggested schedule for those


Yes that’s it. I also added in a few additional nutrients

The apps lets you choose what level grower you are from beginner to expert and the more experience you have the more additives it suggests.
I think if you up your base nutrients to the .51 fl oz per gallon the issue will resolve itself. You are correct , with that nutrient line you shouldn’t need a cal/mag supplement. :v:

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