I go from seedling to 4" to gallon to about a short 3 gal. That's it. Coco - perlite. The 4" plants fill the 1 gallons in about 6 days. They just seem to really respond and the roots are just great. Keep in mind I'm just a hobby grow. I find watering/feeding a smaller container for a smaller...
I've always been a fan of sizing. It comes from a background in horticulture, floriculture, and nursery work. It just means you size the container for the size of the plant. Repeat as necessary. Not sure if is essential but it always worked
I agree . Your on the path of fucking this up. But if you can get some help don't know. Maybe you want to be discreet so the friend thing won't work. Cancel your trip
I would replant them into their own container. Have you read somewhere that said your technique is sound or are you experimenting? If the latter - just leave them and report back.
The discoloration on the stems looks like the result of fungus - probably Botrytis. Fairly late stage as it is affecting the plant tissue above the area of the problem. The white things look "insect related" but not exactly sure what type,
I also think you need to look at the entire situation as it relates to cannabis seeds. The tone of their comments was very guarded and carefully presented. There is a reason for this. They told you they would cover you again.
They will probably just dry a little faster. I've found these final stages to be challenging but necessary. Patience is good during this time
Good luck