i would put them strait into 14l builders buckets when they have grown out of the small brown one's ... they need the root space. i made the mistake of putting them in those square 6 litre atami bato buckets and they got root bound so i would use bigger containers to make sure you give the plant the best start when they start to flower.
heres a pic of one of mine they look identical (five fast buds are on the right )
heres a pic of the big devils in the builders bucket this is what i should have done with the fast buds ...but we all make mistakes huh...
if this dosent make sense its bcoz im stoned on fast bud ... i love it ...so will you am sure
Not got the space to put them in buckets unfortunatly , jus a wee cupboard/cabinet grow !