problem after transplant

i have a 2 and a half week plant and previous had it in a little paper cup when i started noticing the root were coming out of the bottom i re-potted to a bigger pot with john innes no 2 and multi purpose about 60/40 and the plant is starting to turn yellow and leaves are curling down sort of drooping,not sure why before transplant it was growing great only a slight problem with germination otherwise fine, what could be causing this.

does your medium have any available nutrients? whats the PH of the medium

sounds like a deficiency add some N rich plant food. and check PH dont over do the feeding use 1/4 strenth and see if it seems to help if it does then go 1/2 str

the reason i bought john innes is because i have read it can feed for 5 weeks and i wont need to add any nutes but not sure about ph how would i check that