Brown discoloration - pls help ASAP

Por el color que tienen diría que es un exceso de de riego con fertilizantes y eso causa bloqueo de raíces. Lo mejor es lavar raíces y empezar los riegos con todo bien calibrado, ph, ec, etc..

Looking like a classic CalMag issue, you need to buy specific nutrients to get rid of this, else the whole plant will look like that.

It’s looking like your experience a calcium issue. These plants really use a ton of Calcium to grow and it is needed to provide them with additional calcium as they grow. Most bottles of CalMag will do, just follow the manufactures reccomended dosing. Luckily, this is one of the easier issues to fix. I hope this helps.

I agree some of the pics are looking a bit like Calcium issues with hints of some Magnesium maybe. If your soil has not been fortified in a while it needs that about once every 3-4 weeks with amendments, I don't see any information in the diary regarding what you are feeding them. there is a line in week 4 or 3 about you said you hope you don't need to fertilize them at all this entire grow and I think that is not going to happen. Some pics look like it might be getting to much N but it could just be the lighting. One other thing is the soil your using, is it a bagged potting "soil"? or actually soil? Most things sold as potting soils are soilless and just a combination of peat and or coir with some perlite and slow release fertilizers. The problem with fixing a deficiency in real soil and trying to use amendments or making it a "organic/natural" grow is that these nutrients normally take time to break down and the plant needed them yesterday. So I would suggest getting a well rounded feed that has good amount of Micros and Macros and giving it some food. Or just pick up a small bttl of CaMg from a hydro store. One option for this could be a fish emulsion mixed with seaweed. it should have everything the plant needs and they are normally available immediately to the plant. It helps build the soils microbe life and is good for the plants. If not any of the ready to use hydro nutrient lines of feed will do like the CaMg suggested above, these products are good to go and have everything available to the plant right away. they are easy to burn plants with, so read the directions and maybe divide it by half. Its always good to have an option on hand to help fix something that requires immediate attention. I grow in soil and use amendments and always have some CaMg and a good NPK that I can mix up in a pinch. Good Luck!

it looks calcium deficiency to me. If you're using RO water, add more calmag. Good luck!