Soil grow potential root rot?

Hi guys wondering if I could get some advice on an issue.

Started a few new strains in a new place about 3 weeks ago. Started them in peat, and then went to small cups with pro mix hp.

They shot up nice and quick on their 4th set of leaves. But then growth slowed to a crawl. Decided to check out the roots on a couple of them and I noticed that most of them had some really brown roots going on. Leaves aren't drooping but the lower fan leaves started turning yellow which made me decide to inspect. Is it possible to get root rot in Pro mix? I thought there was stuff in the soil to help combat it...

Plants haven't been overwatered. Good drainage. Temps around 85 light on, around 75 off.

Roots aren't mushy just a brownish color. Never messed with dro so I'm not really familiar with root rot. Noticed a few had some new root growth coming from where I buried the stem and its bright white. But I am slightly scared that if I got root rot it will spread to these new growths in a hurry.

Read alot of threads on root rot etc in dwc etc. But can't find much on it in soil. Also my water stays at around 75 degrees and I ph around 6.2

Been using pro mix for years and never had this sort of issue. Could I have gotten a bad batch of soil that was contaminated with something? Should I scrap everything and sterilize?

I'm just afraid that the problem will spread and am about to introduce some clones to the room that are doing great.

Any help on getting these roots back to normal would be greatly appreciated.

you can try H2O2 it sterilizes so it will get rid of the excess microbes causing your rot , and it also releases oxygen which helps your roots stay aerated so they can recover. but you have to figure out why your causing the rot to fix it for sure , it might be over watering , bad soil mix .. etc then work towards fixing it . pics ?

EDIT: H2O2 ( hydro peroxide)

Will try to get pictures in the next couple days.

You have a recommendation on a h2o2 mix? I have some 3% laying around but have heard people say its bad and others say its fine. I won't be able to get to a actual shop for at least 2 more days.

Generally I have always started my seedlings in peat then I go to small cups with pro mix hp. And then finally after cups I got to a pro mix with a bit extra perlite and also some soil with other goodies mixed in when I go to bags.


Will the h2o2 mess with anything in the pro mix? I know it kills the good with the bad when it comes to organics..... Never had to use it so not sure of what its side effects maybe...

Thanks for the info.

well h2o2 is water H2o with an extra (unstable) molecule.** H2o2 ** . so when temp changes drastically or light heat . any trauma and the extra molecule attached releases and leaves H2o , the reaction killz microbs thats why peroxide is used for injuries . so to tell you if its a good idea i need to know if your organic or not cuz organic soil systems need microbs to stay active and producing nutes , so H2o2 interferes with that . but if your getting root root there is obviously something wrong with your microbe balance . here is some reading to explain HERE
you can also use peroxide and after your soil dries ad a microbe blend to your next watering
. but if you use chemical nutrients . there is no need to worry about killing microbes. well i usually use 35% H202 mixed with water at about 3% h202 but ive done as high as 30% h202 and i just got more aeration .

hydro stores sell a 29% solution of h2o2. I use a 5 ml. to 1 gal water and flush with it. then I let the soil go dry, and use a earthworm tea to add the good microbes back to the soil on the next water.