m0useanswered grow question 9 months ago I'd aim for 2 or 3gal pot.
1Gal is ok but so small, 3.7L, Sounds like a lot but its just not that much space. You'll be transplanting again to soon.
I start from a stranded yogourt container 32oz/0.9L Or a 1gal/3,7L >>>> 3Gal/12L >>>> 7Gal/30L I went up one more before but my tent was to small for it. so I max out at 7Gal.
the L is the amount I use, Gal is estimated and not 100% accurate. I use Root Pouches #1 #3 #7
Best Of Luck!