transplanting

i have 5 plants growing right now, and the tallest of the five is about 3 inches tall. they're all in pots a little larger than a regular cup. when should i transplant into bigger pots?

I would transplant soon. I knew I needed to transplant because I saw a root slightly coming out of the hole in the bottom of the pot but you don't really want to wait that long.

You shouldnt really wait until roots are visible, but i wont hurt them only stunt there growth a bit. Peace man

I would transplant NOW, roots that are compacted and bound will starve plant for nutes and hurt more than moving, I moved 1 last night that had only been in 4" pot for 1 week and it was completly bound and roots were at containers sides growing up, it was put in 9.5" pot for final grow and this morning it looks as if it was never moved."No Expert just works for me..."