What do you thinking of these leaf issues?

What do you think about these leaf discolorations?
Yellowing and almost black tips and margins.
I’ve been keeping a journal of sorts here:

  • Soil: 35% worm castings, 35% peat, 30% perlite
  • pH of Water. City water is good quality surface water usually ph 6.8 to 7.
  • Nutrients are root farm, almost identical to general hydroponics floraduo. Currently at 8ml/gal part 1 (4-0-1) to 12ml/gal part 2 bloom (1-4-7).
    Watering schedule is about 3L every 3 days, every third watering has nutrients.
  • 2 Mars reflector 96 (blurple total true wattage 400W) at around 12" height
  • Temps vary from 26 degC in the light to 17 degC in the dark.

I don’t know ppm but have been having issues with low pH so I raise up the water and nute solution to 7-8 before watering and it comes out the bottom at 5.5-6.


Thumb eyeball, I’d guess your mixing nutes a little rich and setting ph too high. Would be easier to be more certain if you had ppm numbers.


I would drop ur ph down to 6.5 or even 6.3.

Of the solution going in you mean?
I’ve been fighting against low pH, for a while runoff was coming out at 5.0.
Would you agree I should flush then at 6.5?
@dbrn32 @Killadruid
Thanks for the insights guys

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Yes the solution going in also are u giving them nutes what kind? And yes I would flush with 6.5 phed water then give them a light feeding.

I’m not really sure. All that perlite and peat may want to be ph’d more like a soilless grow. I have a feeling that’s what you’re already experiencing.


Sounds like he has a build up of nutes in soil and its droppin run off ph. I say a really good flush in my opinion. I had the same issue last grow and a flush got my run off back up. Just a thought

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I personally think that’s bang on. It’s what I am thinking but wanted to run it by the pros just in case! Thanks all will report back in 48 hr

Flushed yesterday with about 10 gallons of water through 4 plants.
Letting it rest now, and going to flush again and test pH going in and out this evening.
Does it make sense to give it some rest before feeding with a light nutrient solution? Or should I follow immediately up with that? I am going to cut my dosage in half.

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Not sure how I missed this but I just realized the feed chart for FloraDuo (which again is basically the same nutrient combo as what I used, General Hydroponics owns Root Farm) has two different instructions one for soil and one for recirculating hydroponics. Well, I had the concentration up too high, using the settings given for recirculating rather than soil. So my nutrient strength was basically almost twice as high as it should have been. :face_with_thermometer:

Also notice from the same feed chart (https://www.ncwgs.com/images/duo.jpg?osCsid=52fd7e3a462bc80aa24030e8a4ce0f69) that the recommended strength pulls back at week 5 of flower which is basically where i’m at right now.

Wow growing weed is full of great learning experiences. I’m hoping this doesn’t have too much of an impact on the grow as a whole! :pleading_face:

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Well dudes, I’m not naive enough to expect the problem to resolve itself in two days, but I am still unsure about the health of this crop.
When I flushed the other day I admit I didn’t pH the water. We have good quality tap water and it is about neutral.
Today I pH to 6.5 and watered merely to take in and out pH. Looks like it has come out reading 5.0.

And the leaves are a bit worse:

Otherwise the plant seems to be in decent shape.

  1. Am I correct that I should give the plants another flush? And considering they are such low pH is it ok to continue to flush at pH 7?
  2. Is it possible these are just genetic colorings? As mentioned the seeds were labelled “CBD master Kush” but I got them free with my order and the seed store didn’t have any background info. There is a master Kush and a CBD Kush but no CBD master Kush as far as I know… Anyways, here is a line on Master Kush: “It acquires beautiful purplish, orange and reddish hues during flowering.” Also found in a similar strain: “partial to purple and blue tones when exposed to colder temperatures during the later stages of growth.”
  3. Could the coloring be a phenotype thing from temperature swings? Tent gets up to 26C with lights and down to about 16C in darkness. I did used to heat the basement and decided to ramp that energy hog down and let it cool down at night…

Thanks again for your help on this one guys!
@Liljoe @dbrn32 @Killadruid

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I would try flushing again at 6.5 and see if it comes up a little bit more.

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Those leaves probably won’t get better at all, not even when the problem has been corrected.

Before you did anything to adjust ph. What did the ph of your tap water read?

You may have a phosphorus issue there. Locked out from ph, or simply not enough in your feed.

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The tap water is about 7.0 spot on, checked it this eve. Interesting about the phosphorus, I assume it would be getting locked out due to low pH. Will keep flushing until I get the pH down to 6, sound right?

Also, instead of following up with more liquid nutrients, I’ll top dress with worm castings and bone meal. Worm castings help to buffer pH, while bone meal will bring pH up and provide phosphorus.

They look like they are rippening up. Also could be in the genes as mentioned above. Low phosphorus also could b an issue at a low ph.
Looks like ur comin to the end so I would just continue watering with higher ph water and let her finish
Here is a GSC at her end showing some nice colours

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I think the crop is responding well.
Here’s Apr 29:

And here’s may 2: