Around day 9 after sprout. This is where I already decided to throw them into the Autopots, as I thought the problems might be caused by the tiny solo cups. It was my own fault though, as I didn't use enough calmag.
I am running RO water, and 0.4EC of calmag wasn't nearly enough. They wanted 0.6EC of just Calmag + 1EC of Canna A/B.
Transplanting into Autopots 3.9gal / 15L:
Adding coppersheet into Autopot, then Airbase. Add straight coco into the base, 1 handful to fill all the wicking holes.
Add coco perlite mixture.
Pre-water every autopot pot until heavy runoff with the same solution you watered your plants with last time, in my case 1.7EC at 5.8PH
I added Azobacter this time as a trial attempt, also Great White on the rootball of each plant.
Add plant into the pots.
Wait 3 days after watering to let the roots seek more substrate.
After 3 days, water once daily til runoff, in my case 3-4L for each pot, every day.
Keep this up for a few days / around a week, then turn autopots on.