A general rule is not to transplant until the fans are at least as wide as the pot. Many wait longer than that.Hi my Critical baby seedlings are now 11 days old approx 7cm high, leaf width approx 4cm. The roots are coming through bottom of the small pots, is it time to repot into the big ones?
For example, Van Stank's still in solo cups:
Bulking up nicely Professor! Going to be huge in 4 weeks .Critical+2.0 at day 34 of flower. She's the biggest and baddest out of 10 strains so far. Still another 4 weeks left until harvest and things could change by then but at the moment she's kicking ass and taking names!