Grow 2 - Critical Purple Kush Fem by Seedsman

Yup, just bought one. Thanks guys


Update: I am at Early Veg Day 7/14. Total: Day 17

I bought temperature/humidity reader and water temperature reader. I am also currently distilling water and will be able to switch from tap to distilled tomorrow.


Temperature: 35C / 95F
Humidity: 24%
Water Temperature: 25C / 77F

I believe my temp needs to be lower and my humidity needs to be higher, any advice?

I have also seen some yellowing on the small leaves the plant initially grows, is this a problem? I’ve heard that these leaves come off over time.





  • (SomeGreatAdviceOn AllGrowers): {:green_thumb:}: (If Your Temps Are High, I Would Advise On using Hydroguard In Your Grobo):

  • (I Would Try These Methods To help With Your Temps): (Hydroguard Might Help):

  • (Lets Hope The Dieing Leaves Don’t Escalate):

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:crossed_fingers:t4: :crossed_fingers:t4:

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Hey @Spaceman, you are definitely right on your temps. You wanna shoot for mid 70’s F for internal and high 60’s for water. The water temp is ok as long as you use hydroguard, it’ll help fight root rot. As for the iinternal temp…what temp do you keep your place at? Does it seem liike your light inside turns on and off when it shouldn’t?


I have switched to distilled water.

I was unable to get Hydroguard as it is sold out but purchased (what appears to be) a similar product called Rhizotonic (seen in image). Would anyone be able to advise me when I should put this product in my reservoir, how much they recommend and how often I should dose this product into my reservoir? Thanks

On the Rhizotonic bottle it says 40ml per 10L and to dose 1-6 times daily.

As I have noticed what I believe to be root rot, I have done a single 35ml dose a couple hours ago. (Root picture was prior to dosage)

@FireGuy My apartment is usually around 23C-25C but I currently store my Grobo in a large cabinet as the air pump is too loud. I believe this is what is causing most my high temp, low humidity problems as there is low airflow, in a small space and has the boiler in the same cabinet causing a lot of heat. Ive seen others on here complain about the air pump and am looking to replace it for a quieter one as soon as possible, but for now, will have to stay in the cabinet.

As for the lights, it would be hard to say as the grobo is in a cabinet. However, I have the Grobo Premium and have never noticed the blue light coming out the screen go off and I am currently growing a photoperiod feminized seed. Is this something i need to lookout for?

(Prior to first dose)


Late Veg day 5 / Total: Day 29

Humidity: 42%
Room Temp: 26C
Water Temp: 22C

When cleaning the roots a couple weeks ago, I think I was a little rough and damaged the roots, knocking off many of the pistol roots that spur out the main roots.

Since then, I have soaked them in Hydrogen peroxide twice and cut off a total of 4 yellowing leaves over the course of 2 weeks.

I feel like my plant is growing very slowly / mostly in the roots and little in height or leaves.

Still waiting for Hydroguard to arrive so using Rhizotonic.

Besides the root rot, I’m not sure what is going wrong, any ideas?


Also, when draining and filling yesterday, my water level has gone back up to the top tap despite me being in late veg. I believe the water level was lower before I drain and filled which is making the bottom of my coco pod damp. Any reason for this too?


If this is your first drain and fill in Late Veg, it will go to the high level. You might have to move your pod up a bit to keep it dry or use some fans blowing on it…

Paper towels help a lot too to sop the moisture up… takes awhile and some effort but usually helps.

Honestly, your root zone didn’t look terrible to me. I see individual roots coming out of the main tap roots and it looks more like nutrient stain from bottle #5.

It looks like you might have damaged some of the root zone so it could be affecting the plant up top. Using the hydrogen peroxide might have killed all good and bad bacteria present in the area as well which I can only imagine acts as a sort of environmental shock for the root zone.

No idea on that Rhizotonic product, I am going to google it a bit just to know a little more about what’s out there. It sounds like you have to use a decent amount of it per day; can’t imagine it’s cheap either!


I see. Yes, its my first since moving into Late Veg, thanks.

Overall my plant just seems a lot smaller / undeveloped than many others I’ve seen on here when at this stage of their life.

@Todd.grobo @Azuri @SterlingNico @Rich @rainstorm3 @chris_barfield @SilverGrobo @Bplatinum9 @bjorn @Stephen

Any help is greatly appreciated!


I think so too. However, it must’ve been at least 2 weeks since I damaged the roots and the only other stress I have caused since then is soaking the roots in hydrogen peroxide twice and cutting off 4 leaves.

So I would’ve assumed I have given it plenty of time to recover. I have a photo of the bottle further up in this post if you want to have a look.

Thanks for the help

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Looking up at my posts, I’d say its been about 10 days actually, not 2 weeks.

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Hmm yeah I saw the time stamp from the previous post… either way, round up to 2 weeks is fine haha!

Um, well I hope she will start progressing for you soon. She’s definitely a bit behind a normal Late Veg 5/14 plant, but, not looking too bad I suppose…

Which 4 leaves did you remove? Were they larger fan leaves? Or possibly lower dead stuff…? Just curious.

Only thing I can think of is that the root damage and defoliation combined with nuking her root zone with h2o2 has been stunting her growth by at least a handful of days.

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How are Bottles #1 and Bottles #2 looking for you btw? Is there a lot used from them up to this point?

I was reading that Rhizotonic can raise pH of reservoir, but Grobo should fix that… However, if there’s possibly a calibration error with the pH probe it might really throw things out of wack. Just checking.

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Its important to grow a full grow before adding anything to your grobo.
I can’t stress this enough, I know many growers just try to do their best and get on allgrowers and take advice but if you start off understanding what your grobo is capable of first than it will help you going forward.
Bleaching your roots is harmful because it kills good and bad bacteria, its a lot for your plant to handle.
Adding your own products to grobo nutes is not advised because additives may not mix with grobo nutes.
Grobo grows just fine all on its own and a bit of hydroguard to keep bacteria in check.
This plant is stressed out and may not reach its potential, my suggestion is to stop any additives and hope it recovers or start over taking care to grow without adding anything else except hydroguard. :eyes::seedling:


@pyromancy They were the first 2 leaves the plant grew, which curled.

You can see them in my post 13 days ago. I then cut off another two a few days later which I took a photo from.

Bottle #1 is fine, not a lot used. Bottle #2 is almost finished. Will probably have to switch it out later/tomorrow.

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Bottle #2 is almost gone? That’s not good.

I opened my first Bottle #1 and #2 back in September, and I still have about 2/3 left of each bottle… That’s not good.

You probably have a pH probe error…I would recommend doing a health check and calibration ASAP. That is probably the problem with your slow growth, especially if you’re using additives outside the Grobo

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Thanks @Bplatinum9 Ive only added 1 dose of Rhizotonic every 1/2 days in order to try hold back the (potential) root rot until Hydroguard arrives.

@pyromancy I see. How do I go about this? Calibrate them via the app? Anything else? Should I buy a probe Kit to measure it?

When I started my grow I was using tap water, but I have now been using distilled for about 2 weeks


Ah okay, well I did read back and see you were using tap water, which can definitely make the #1 and #2 be used much more than distilled or RO, but for how long your grow is, and the fact you’ve been using distilled for the past two weeks, I don’t think it should be anywhere near an empty bottle at this point! Seems suspect for sure.

You will need to get a pH 4.0 and pH 7.0 solution to calibrate properly. They are available on Grobo’s site or on Amazon… possibly even at a hydroponic store locally too? I am not sure, but I wonder if they are available at pet stores for aquarium fish pH testing and such… Not sure.

I would suggest Bluelab solutions because that is the brand of the probe inside the Grobo, and is also a trusted brand… but you can definitely look around.

The Grobo tests pH every hour from what I’ve heard, and when that much is gone from your bottles it means the Grobo is constantly adjusting the pH. It shouldn’t fluctuate enough to warrant a whole bottle of pH Down being used.

I mean, the Rhizotonic is known to raise pH levels so that could be why #2 has been used more, but still seems like a lot. A little bit goes a long way with the pH up and pH down.

Also, how is Bottle #5 looking? I have heard that when the EC meter registers tap water it does not dispense bottle #5 from what I’ve heard from Grobo support. If #5 isn’t being used, and/or the pH level is out of whack, it could explain the orange/yellow tips on your leaves also.


Try using 1/2 reversed osmosis mixed with 1/2 distilled water.
If this is your first grow you shouldn’t need to recalibrate but under the maintenance tab there is a calibration tab.

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@pyromancy @Bplatinum9 Thanks boys!

I don’t have 4.0 and 7.0 solution so I will order some now. However I just did a PH test using my fish tank PH tester and the colour showed it could be anything PH 6 or lower so I think you’re right.

This is basically my first grow as I drowned my first seed, so thought it would all be correctly calibrated, but that is looking like the problem.

Once again, very helpful, thank you. Should be able to calibrate by tomorrow latest and I will update this post.