Plant needs help

Something's going wrong with my 2nd grow. Have 2 plants in the tent (3x3ft under 600w LED in soil) and one of them has a problem, not all over but on a few branches and just on one of the plants. Don't know how to correct it or if needed keep it from spreading. Hoping someone can help.

Possible contributing issues. I did mistakenly buy Miracle Grow soil (with nutes in it) and only fed it twice with diluted nutes and just water since then, over last 2 weeks. Did that because I noticed tip burn and attributed it to over nutes. Tent temps had gotten into 50 degrees f when cold weather set in and the lights were on 12/12. Added a small tower heater to keep things around 70f. Tent moisture has become a small issue because of tent temps and humidity causing moisture to condensate on inside tent walls (RH showing +- 65%). Cyber Monday dehumidifier on the way.

Instead of a dehumidifier why don't you run your exhaust fan on a timer to control humidity. Honestly 70 degrees and 65% humidity is as perfect a vpd as you can get. You need better air exchange not a humidifier and I speak from personal experience.

Not sure which way it's off but that looks light something is off with your potassium? I don't grow in soil but I know enough that you should never use miracle grow. I bet someone will tell you to transplant it into some good soil.

Is it dangerous to repot just a flowers are just starting to show ?

Don't really know but I would strongly believe that your soil is much worse for your girls than any damage from repotting.

Think I’ll try, already have one plant looking great while in identical soil so planting won’t be a total lost if one plant doesn’t survive.

I've read other people having similar issues with same plants, same soil(MG) with one doing well and others not.

Doesn't it have little nutrient release beads in it or something like that? You get a bunch more in one pot than the other and who knows. Maybe one pot is draining better then the other.

https://www.growweedeasy.com/miracle-gro-soil-for-growing-marijuana

Thanks Shayne. Wish I had seen this before buying two 50 gal bags, I’ll return unopened one and see what they have as an alternative.
Live and learn.