Yellowing tips on new growth. Opinions?

Hello again everyone,
Here we go again, new grow new problems.

So, this plant is 30 days old from when she broke ground. Growing in a 70/30 Coco/perlite mix. I am currently feeding the Week 2 mix of Advanced Nutrients pH Perfect Sensi Grow Coco. Giving 2ml per ltr of each nute they have. EC of the mix is 1320 (660 PPM). pH of the mix is 5.7. Run-off EC was 1386, pH was 5.1 the day before yesterday, 5.4 last night. I water to at least 20% run-off daily, I don’t know why pH is dropping already :confused:
As for lights, I’m using Electric Sky ES300 V3, 32 inches away from the plant, 80% intensity, DLI 21.

I am in correspondence with Advanced Nutrients as well on this issue but would like your guys input / opinions also. AN told me I need to up the feeding to their Week 3 schedule (3ml of the base instead of 2ml, but keep all other nutes at 2ml).

Pics of the plant below:

I’m planning on manifolding the plant, can I proceed with topping her and start the manifolding process? She’s showing 7 nodes so I don’t want it to get too late.

Thanks in advance again for any help everyone :slight_smile:


I’m assuming plant is a photo If so I would Let the plant grow a few more nodes before topping. Looking good :+1:


Hello @kellydans I don’t mean to contradict what you’re saying, but how is the plant looking good if the new growth is yellowing? I’m also already experiencing a pH drop and it’s only been 6 days since I transplanted to the air pot you’re seeing her in.

Regarding the topping, how many nodes would you suggest? Most methods I see for manifolding are ‘top above the 3rd node when the plant has 6 nodes’

Thank you in advance for your time.


I was watching a video last night talking ph drop.
The lady made a very convincing argument that most always, ph drop is related to “bad bacteria” out numbering good bacteria.

It’s possible that the media is slightly anaerobic.
Adding h2o2 to your mix can help kill the bacteria and add oxygen to the media.

The h2o2 can be used through out the entire grow, or once to knock the microbial count down, then follow up with some form of good bacteria like bacillus amyloliquefacien.

If you just translated a week ago, the slightly discolored and trwisted new growth could simply be a response to the transplant stress :man_shrugging:

The plant does overall look very good :+1:
I see what you talking about with the yellowing, and paired with a dropping ph, I would also be a little concerned myself.

I grow mostly in coco-coir and perlite myself and I use h2o2 regularly and if this wasy grow, that’s exactly what I would do.
I’d mix my feed as normal and add some h2o2 and for the first time, I would water with the h2o2 solution till my runoff was coming out at 5.8…

That’s my current grow if you want to see my methods and what they produce :blush:

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Overall plant looks good i see nothing to be worried about. (Topping) I like to have a little more framework to work with more buds. Once you top upward growth will slow down . HAPPY GROWING @MagicCultivator420


@1HappyPappy wow, I just skimmed through your journal quickly, you grow some nice plants! Well done! I’ll definitely give it a more detailed look and read all the posts.

You’re saying to add h202, won’t that kill my beneficial bacteria? I’ve been feeding Voodoo Juice, Tarantula and Piranha (Advanced Nutrients’ beneficials) for the past 2 weeks :confused: If I had to add the h202, how much ml per ltr?

@kellydans thank you as well for your input, provides some peace of mind at least knowing some other members are saying there’s nothing of concern. This same issue happened to me on my first grow also, then the problem resolved itself on it’s own when I got close to flip to flower. 2nd grow had something similar, and the issue got resolved once I started feeding twice daily instead of once, but my pH tanked to 4.5 in the final weeks of flower.

This is where I get confused now. I have 3 different opinions:
-AN said up the base feed from 2ml per ltr to 3ml.
-1HappyPappy suggesting h202
-Kellydans saying leave it as is and all is fine


Hello everyone, just giving a small update, took run-off readings today and they came in at 5.5 - 5.6 :slight_smile: slowly creeping up back into range :smiley:


Thank you my freind :blush:
I wouldn’t call myself an expert, but i have learned growing good cannabis can be very easy and doesn’t really take alot to do so.
I try to do things as simple as possible and get great results most of the time :sweat_smile:


It most certainly will kill both good and bad.
I don’t use microbes much so it’s easy for me to not worry about killing the good.

The idea would be h2o2 will wipe the slate clean so to say. You can reintroduce the good microbes afterwards.

But honestly the plant really doesn’t look bad at all and may not amount to anything more then what we see now.
And this could be the on set of ph issues coming :man_shrugging:.

I’m of the mind set ultimately it will not hurt the plant, it will kill both good and bad microbes though so you would need to reintroduce them.
But imo its kinda like hitting the rest button for the root zone if that makes sense :thinking:


I would dilute peroxide by 50% and water media to runoff. Like stated that will ‘reset’ your coco. Adding beneficial microbes after just gives them a head start. I would also consider running Mycos. You are using synthetic nutes so not sure how that affects the biome in the root zone.

Plant looks generally fine, if manifolding you want to get on that right away. Seeing something ‘odd’ after transplant is also normal. I would also recommend upping the nutrient load to around 900 ppm/1.8 EC.


Thank you @1HappyPappy and @Myfriendis410 for the hydrogen peroxide suggestion. It makes sense resetting the coco and starting off from a clean slate and reintroducing the beneficials again afterwards. Took pH runoff numbers again today, dropped to 5.4 again from the 5.5 - 5.6 that it was yesterday. So, I have this hydrogen peroxide (6%):

@Myfriendis410 you suggested dilute with 50% water, I’m watering around 1.5 litres a day, so I put in 750 ml of this 6% with just plain RO water and feed water the plant, or dilute it at that ratio and put it in with my nute mix?

I upped the EC/PPM as you suggested for today’s feed, I started Week 3 of the feeding schedule which came in at 1660 EC / 830 PPM. The plant is getting some mild brown spots on the top most leaves now :confused:

I’ll proceed with the manifold shortly then as per your suggestion @Myfriendis410, just give her a day or 2 to get used to the Week 3 nutes and I’ll start by topping her.

Thanks again in advance everyone, it is such an awesome community here.

If you mix peroxide with water that contains any solids (like nutrients) it will break the peroxide down almost instantly and be useless. When diluting peroxide always use R/O or distilled. With 6% I’d go 2 to 1 water/peroxide.


This is not exacty accurate from my understanding and experience.

Generally, hydrogen peroxide is added in small quantities to the central reservoir in your hydroponic system. Once added, here is how it works, in simple words:

  1. The molecules break down slowly into water and a single Oxygen atom, a free radical.
  2. This free radical is a very volatile agent, which can react in multiple ways.
  3. If it comes into contact with an organic cell, like a bacteria or virus, it damages and destroys it.
  4. If it comes in contact with another oxygen atom, it forms an O2 molecule.
  5. This molecule is healthy essential for the plant roots.
  6. The whole peroxide molecule also reacts with any free chlorine in water to form O2 and hydrogen chloride.

It dosen’t react to all solids or salts/minerals and can be very stable in a synthetic nutrient solution. Most agree that half life is upto 80 hours in a sterile system and as short as a few hours in heavy organic environments.

I’ve read alot about h2o2 in hydroponics as I got alot of slack last year about switching to running it instead of microbes. But i made the switch anyway after lots of reading different studys and I’m very pleased with the results.
I’d be very interested in any date you got about it reacting instantly with nutrients though

It’s worked great for me this past year.
My reservoir temps get really high and with hydrogaurd it would always start to stink and then go anaerobic and get slimy :confused:
Sense switching to h2o2 i have no smell or slime, unless I forget to top it off at least twice a week.
It lets me know if I forgot :joy:

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Heh, got 2 differing opinions here :sweat_smile:

@Myfriendis410 So I mix in 500 ml hydrogen peroxide to 1 ltr of water and water the plant with that. After this watering, do I feed my Week 3 mix a few minutes later, or do I skip feeding for that day to let the hydrogen peroxide mix work, then resume feeding the following day? I only need to water with hydrogen peroxide once correct? And then I can start reintroducing my microbes again?

@1HappyPappy I like the plants you grow from what I saw, so it shows that you definitely are getting good results. Your system unfortunately won’t work for me since I use microbes :confused: I understand your concerns about the reservoir and trying to find a solution with h202. I plan on installing an automated watering system with a 50 ltr tank in the future (it had to be this grow but didn’t have time to), and honesty I get high temps when summer is approaching too, so I’m quite worried about bad bacteria forming in the reservoir. Usually a 50 ltr mix would last me a week for 3 plants. In my last grow the 3 plants were drinking 7 ltrs a day between them, I was feeding twice a day from the beginning of flower to avoid the coco drying out. Hydroguard is not available in Europe, and importing it from the US made the price ridiculous. I had read on these forums that the coco should act as a buffer from bad bacteria in the rez, but need to try it out and see results I guess cause it is something worrying me about installing this automated watering system down the line.

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You can add the h2o2 to the nutrient solution if you want to was the only point I meant to make.
You don’t have to skip a feeding.

I am convinced that the h2o2 will not react instantly if any at all with synthetic nutrients.
If I’m wrong I’ll apologize and change my prospective, but I need to see some real data behind that claim because it’s 100% contradictory to my understanding and experience.

And you should only have to do it once, and it’s really as easy as doing things exactly like you normally would but just use h2o2 instead of microbes.

I’m so sry I have kept forgetting to give the amounts :sweat_smile:

The recommended amount of 3% (what i use) solution of peroxide per gallon of water in hydroponics is around 5-15ml per gallon, but twice that is perfectly find, i add alot more to my reservoir sometimes if i forget and it’s smelling or something.

I think me and 420 agree on everything else except the half life of the h2o2 in a nutrient solution.
The h202 is very much active way longer then it will take to flush the plant.

I’m not saying you can’t flush with h2o2 in RO water because you certainly can if you want to.
I just don’t think theres any reason to, but it want hurt anything :blush:

But theres alway multiple opinions and lots of times they all lead to the same place either route you choose mine or his dosen’t really matter :man_shrugging: both will get you to the same place.
It’s just I don’t believe there’s any science suggesting h2o2 into a synthetic nutrient rich solution is almost instantly useless and im a stickler for following the science.
Again, I could be wrong but I need scientific proof to change my mind.


I’m going out to my tent and pour a splorp’s worth of h2o2 into my autopot res now! Using AN pH Perfect nutes

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That link is very misleading and uninformative :confused:.

What kind of environment does it need to be in :thinking:
It doesn’t say, it basically makes a claim rather then support one :man_shrugging:

Here’s a couple of different sources that are more reputable and informative.

From Wikipedia, ask it the same question and you’ll get the page if you want to read it all.
Wikipedia can ge altered by any so the 2nd is from the Environmental protection agency.

This one from the EPA has a very detailed pdf if you want to check it out, it pretty interesting.

The EPA study is from 2007 I think so there could be new science I’m unaware of but I cant find it, if I’m wrong I’ll change my position.


Thank you @Myfriendis410 and @1HappyPappy I didn’t mean to start a debate amongst you two :confused: I appreciate both your information. Got some good news, while so far I haven’t proceeded with the hydrogen peroxide, I started the manifold and also the Week 3 feed which is 830 PPM. Run-off pH was 5.4-5.5 The plant is looking quite good now in my opinion, what do you think? (Sorry for the white tape, cracked a branch a bit when manifolding)

Judging by how it’s looking, I don’t opt for the h202 for now?

Just a side question, I noticed today when taking DLI readings that the DLI is different when I’ve got the tent with 2 flaps open as opposed to 1 flap open. Noticing a difference of 3 DLI with 1 flap closed, I assume with both flaps closed it will be slightly higher. So, when taking readings and following a chart like the below, are these charts based off of when the tent is open and the grower is taking readings, or what it should be when the tent is closed?

Thanks as always everyone :slight_smile:

You are very welcome.
And don’t sweat it none :blush:
Debating provides a major boost to personality and academic development.
To describe in simple words, debating enhances a persons research, reasoning, and public speaking skills.
It can be a powerful learning tool.

I totally agree with this decision :+1:

I’m no help with the DLI stuff.
I dont test mine, I look up my lights on YouTube and watch others take readings and i just use there hanging heights :sweat_smile: I’m just lazy in that area I guess :rofl:

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