I've been putting my plants out on the balcony around 4-5AM (I know, but it's nice to have something to do if the sun's gotten me up that early anyway!). Summers in Berlin are very bright since we're so far north, with sunrise before 5 AM. The balcony faces east and is only partially recessed, so the plants get good light until around 3-3:30 PM. Then if it's not overcast, I bring everyone inside to sit at my western-facing windowsills. I feel so bad for them because they do crane towards the light once they're inside, alas it's all I can offer them.
This was the earliest I've put a seedling outside (starting 8 days from seed), and she seems to be happy.
I added two BAC biotabs (https://www.dutch-headshop.eu/bio-tablets-soil-improver-bac-12-pieces) to the 3gal pot once I saw a fourth node coming in 13 days from seed. I think I may have did this too soon actually. But all is well so far.