First Grow Problems - Yellowing Leaves

Hello, OMG this just crept up on me. All this yellowing showed up. I had the lowest leaves yellow a few weeks into veg, but I thought the cause was me splashing nutrients on them. Now the yellowing is climbing up most of my plants at different rates. I stopped the nutrients a week ago just to see. I started Cal/Mag two weeks ago…it seems I got a late start to that. Looking at the deficiency chart its hard to tell what it it. Any help would be great! I’m starting week 7 flower. Am I gonna make it to harvest

  • Strain: Auto-flowers (Amnesia Haze, Northern Lights, Blueberry)
  • Method: Soil - FF Happy Frog 100%
  • Vessels: Fabric pots
  • PH of Water = 7.1, Solution = 6.23, runoff = 6.05
  • TDS of Water = 20, Solution = 1650, runoff = 4,000
  • EC of Water = 3.2 mS, nutrient solution = 2.3 mS, run off = 5.6 mS
  • Indoor
  • Light system: HLG 3 x 260 Rspec XL
  • Temps; Day = 80F , Night = 73F
  • Humidity; Day = 45%, Night = 40%
  • Ventilation system; Yes, 6 inch, 2 x oscillating fans
  • AC= 8000 btu, Humidifier = small in tent (not using) Large in outer room set to 55%
  • Co2: No

Thanks for reading/helping!

What are you supplementing with? VERY high runoff TDS for Happy Frog. Double check your PH meter as that looks like N deficiency but you have high salt numbers. @MattyBear @Covertgrower @MidwestGuy take a peek too?


So I’m using 8ml/gal Big Bloom, 5ml/gal Grow Big, 5ml/gal Tiger Bloom 2x/wk. My pH meter broke so those are old values, but should be consistent with what I was inputting. I used sledgehammer at week four and started cal/mag 5mls/gal 1x/wk. @Hellraiser, @WVGROWER, @MrPeat, @beardless

I suspect that you have an excess that is either causing a lockout or a PH departure doing same.


This is for soil grow.

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With that low of a PH…the nutrients are definitely getting locked out. If your meter broke then I would be grabbing a new one asap. The high ppm runoff is high indeed like Myfriendis410 stated but all of that isn’t available to the plant necessarily. I’d focus on getting your meter, and getting back into proper ph range. But dont try correcting it by going in with high ph water. Just pour regular water in ph’d at 6.5 until your runoff matches. It should also help clear some of those salts up.


Agree with the others about pH and VERY high runoff. If you’ve been feeding heavily then you probably have salt buildup which is going to make pH very hard to control.

If they were mine I’d get a flushing product such as Sledgehammer or Florakleen to get rid of the salt buildup. Get your pH corrected, then correct for PPMs (should be ~1000 or so) after you have pH under control. Happy Frog will naturally go back to ~6.5 when the salts are gone. Be aware that autos are more sensitive to high PPMs.


Looks like we have excess and deficiencies.
I would agree nitrogen deficiency, but then we’re dumping back in 5ml of grow big.
I think if a flush is done again, and start over with the schedule we can make this right. I’m not sure which part of the TDS is high, either flowering nutrients, or too much nitrogen. Too much nitrogen can lock out phosphorus, and potassium, so be careful with how much you feed it after the reset.
The PH can be reset after the flush and you should do alright.
I would also recommend next time to run your lighting a little less. How far on the potentiometer did you turn it up to?
Only reason why I ask is your plants look the same as mine when I turn them up too high, and can’t keep my hand off the potentiometer.


THANK YOU All!! Somewhat relieved by your responses. Sounds like my ladies are salvageable.

Ph meter tip replacement was ordered 2 weeks ago, but it seems COVID delays will have me running to the store for this “essential” item. Any emergency pH meter/stores preferences until I get My Apera tip replacement? Cost doesn’t matter that much.

So it seems most agree I have locked out my roots causing nutrient deficiencies. Possibly N,P and K. And that a flush is needed to “unlock” my roots for uptake. Should I flush with pH adjusted water to 6.5 or with pH adjusted Sledgehammer to 6.5?

Do I wait until leaves clear up before going back to the FF nutrient schedule? And should the FF schedule be reduce from 1/2 dose to 1/4 possibly?

I wish I knew what the potentiometer was on my lights. I remember reading about a switch but left it at factory default. Problem?

Thanks again!

Hi Mr. Peat,

Just curious. Do you use all the nutrients in this schedule. I’m only using the trio + Cal/Mag + sledgehammer. Do I need any of the nutrients in the orange and purple sections of the schedule for auto flowers?

Sparky 27

Yes, definitely salvagable.

No need to pH adjust the flush. Just flush with distilled or RO and one of the desalting products mentioned. RO or distilled water will take on the pH of the soil it is being put in. I’ve found that Happy Frog goes right back to 6.5 once the salts are gone.

I recently did a flush of 10-gal pots and I used 3 gal of Sledgehammer solution (10ml/gal) and followed it will 3 gal of just RO to wash out the residual Sledgehammer.

The damaged leaves won’t heal or clear up. I wouldn’t worry about them, and I would cut those that won’t take up light off (those most seriously yellowed.)

You’ll want your runoff to be ~1000 PPM at that stage. Fix your dosing to achieve that level. Keep in mind that saturated soil won’t absorb nutes, though it does help to give a light dose 1 gallon of pHed nute solution immediately following your flush. You will try to get your PPMs back to ~1000 on your next watering after your soil dries out following the flush. You will need to add back some cal/mag too as will have been all washed out. Most won’t recommend nitrogen during flowering, but you will have to add some N back too since you will have washed it all out.

@dbrn32 Can you please help this person adjust their lighting?

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I am running all the FF nutrients. Their feeding schedule is pretty good. As for Autos, I have seen posts where Autos don’t like nutrients as much as Photos. I stopped feeding my Autos any nutrients.

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Thanks @MidwestGuy. That’s awesome clear help. Running for a new meter. Let you I now how it works out.

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Hlg-240h-c2100a driver? On top of drivers should be a little black rubber plug. Pinch with fingers and pull it out. Underneath is small screw you can turn with #1 Phillips screwdriver. Its plastic so don’t horse on it, to the right is more light and to the left is less light.

Backing off light will slow photosynthesis a little and help give you some time to dial them in. Them gradually increase power. Look to get to maybe 16-18" at full power for flowering.


Found this today looks like nutrientburn

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It’s interesting because I hear some grower say no nutrients with auto’s works out just fine. Mmmmm. Wondering if I should go with no nutrients the rest of the way? Maybe just Cal/Mag one a week? Anybody think that’s a bad idea? Two photos attached 24 hrs apart and 12 hrs after my flush and cal/mag treatment. Hard to tell if its having an effect. Water in soil is almost drunk up and I’ll look to water today/tonight.

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