What’s happening here? Seedling yellowing from the centre

Umm…no. I don’t have a TDS meter. Not sure if there is another way to measure it.
Also, if I’m honest that all feels a bit too technical for me right now…
Thought I’d try and focus on getting the ph right first. Baby steps :joy:
I understand ppm and ph work in tandem but I feel like that’s all a bit much for me at the mo. :frowning::frowning::frowning:

My whole pot is only 7 litres so a couple of gallons I feel would drown it… am I being too cautious?

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Well you can’t drown your plant in a single watering, and typically a flush takes 2-3 times volume of pot in water. You can try without measuring ppm but will be more difficult to be successful.


@dbrn32 is taking care of you here but you definitely need a tds meter, that’s a tool you NEED.

Sorry I was off for a bit, my days off and had a friend from another area come into town.


Thank you @dbrn32 and @Nicky

Ok so sounds like I’m still being too cautious with watering.

I’ll get a TDS meter as soon as I can and report back!

Thank you :smile:


Why do you need a TDS meter? I don’t and have never used one and I grow in soil and coco

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Very difficult for us to help without that information.


Yes, it is all more technical than I had first imagined also. You’ll get the hang of it.

As far as watering, you water sufficiently at one time to get water coming out of the bottom in order to measure. That will not drown the plant. What is bad is repeatedly watering when the soil hasn’t dried sufficiently.

You can do it; heck I harvested my first two plants a week ago and I still can’t believe it!


[quote=“CalamityJane, post:1, topic:52516, full:true”]
Hi everyone!

I’m a compete newby to this so thought I’d start with something relatively easy, GG4 autoflower.

Basically the seedling (planted 16th Aug) is turning yellow from the centre. Leaves look a bit crispy but they’re actually still quite soft and flexible.

  • GG4 Auto
  • Method: Soil (peat moss composition) + perlite
  • Vessels: Pot
  • PH of Water, Soil PH a little high: 7
  • Indoor
  • 300w LED (currently using veg light)
  • Temps; Day 28 (not sure about at night)
  • Humidity; Day (44 but recently added wet towels now increasing to about 65) I know this is a bit low.
  • Ventilation system; Yes - 4” carbon filter
  • AC, Humidifier, De-humidifier - none
  • Co2; No

I’ve been lightly watering it every few days or so in the first week. Then added seaweed extract w/ water (mix: 15ml extract to 3 litres water) around day 9 (maybe too early for nutes).

As humidity was low I popped a cut off bottle over the top of it. Has this intensified the light and burnt it, maybe?

Any help is appreciated.
Thanks all.


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You’ll need to start your own thread but sounds like your PH might be out of wack, no need to feed yet if you have soil because the nutrients are in the soil.
Until you have a runoff that reads below 800 ppm your fine to just water for the first 1-5 weeks.
. Yellowing may be because it’s PH is out of wack and thus it can’t absorb nitrogen. Not for sure but that’s my first thought considering the information given

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Thanks everyone for your continued input.
Apart from the ph issue which is slowly improving Iis it possible I have a phosphorus deficiency?
I was looking around and found this, which seems to be exactly what is happening to mine.
Credit to @Redeyedranger

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Something to think about. Didn’t a plant that young would have a nute problem very interesting. If it is a phosphorous deficiency problem i just learned something new. Thank You for posting it @CalamityJane.

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Ok folks, so I wanted to share with you where I’m at now.
It’s not looking great.
Yesterday marked her 6th week birthday and looks nothing like @Se7en’s at 6 weeks old.

I don’t have my TDS meter yet so appreciate I’m still watering a bit blind so here’s what I’ve done (rightly or wrongly)

Flushed twice with ph adjusted water;

1st 16th Sept: Soil ph at 7.3. Watered with 2l ph 5.63 water.
Run off ph 6.3

2nd 21st Sept: Soil ph 7.1. Watered with ph 3.6 water.
Run off 6.16

(this is Sainsbury’s bottled mountain water which is still meant to have all the minerals in but after doing some research I found out perhaps not as effective as good ol’ tap water)

I don’t understand why my soil ph is not lowering faster.

New growth is nice and green but tips are browning and curling almost straight away.

Are those pistils I see? :grin:

Temp: 29°c
RH: 42%
Light is only 19” from top of canopy - too close?

My temp is too high and my RH is too low - how can I get them right?
Not sure how to lower temp but increase humidity - might be a stupid question but would ice cubes in the bottom of the tent work?

Also what has caused those awful dead/burn marks all over the biggest leaves? Have I burnt them with the light being too close it is it nutrient (or lack thereof) related?

Thanks guys. Not sure im going to really get anything off this but I’ll keep pushing.

Thank you

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Was meant to tag you all… see above comment… brace yourselves! :joy:
@Deepsix @PP3121 @dbrn32 @Spiney_norman

I believe the tips of the leaves with the burn effect could be nutrient burn, but other than that it looks like she has recovered well :v:t2: Sainsbury’s? Are you fellow UK citizen? :slight_smile: If not I didn’t know Sainsbury’s was anywhere else :laughing:

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Ah-ha @Se7en I couldn’t possibly disclose my location… :wink: even though I think I inadvertently just did… should have done my research on Sainsbury’s intl. first! :sweat_smile:
Let’s just say, I also used 3 pronged plug sockets… :grin:


@Se7en But I’ve barely used any nutes on her. Just a small amount of seaweed extract, and that’s only twice and it was a really tiny amount.
What about raising humidity but lowering temp? Days have been warm recently and like yours, not going below 30°c - too warm.

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That’s too low going in. I always try to keep within 1 point of my target. When That’s not enough I just keep pouring more through.

Not all of those minerals are mobile, that is why you see so many people use distilled or ro water and add everything. Even super soils will usually get some type of micronutrient put into them.

If i had to guess, looks like they were left wet under lights on.

Ah, thank you @dbrn32

It seems I am trying to counter the ph issue incorrectly. My train of thought was that if the first water made no difference to the soil ph I would need to further lower the ph in the water I was giving it - actually what I need to do is give it more of the correctly adjusted water. :+1:

I see what you are saying about the water types… it doesn’t matter what water I use as long as I balance it correctly with ph and/or supplements.

I think it’s unlikely to be water on the leaves, not that much anyway. I’m always really careful to avoid the leaves when I water. What else do you think it could be if we were to rule that out? Just curious.

Thanks so much.

Light damage. But probably more so because there was already tissue damage to leaves than just saying your light is too close.


Brilliant answer @CalamityJane :laughing::laughing: I have those same plug pockets :sweat_smile:

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