when should i transplant??...and what size pot??

I have my baby in a one of thos little styrofoam cups and its been only a week a few leafs are showing now not that tall yet....so I was wondering when should I put it in a a different pot like what week should I do that...and what size pot should I put it iin???...thanks

You should transplant when your roots are looking dense in your media ie they are running out of room to grow. Just pop ya plant out of its pop when its a little drier and take a look.

I am only on my second grow, on my first i went from a small pot to a 10ltr, then to a 15ltr. This time i went straight to the 15ltr, and i think my plant didnt like it. as the next time i watered with the same strenght of nutrient, i got nutrient burn and the previous watering i didnt. And it took abit of time to recover. Also i am finding that i only water my plant every 7 to 10day at the moment because its not big enough yet to drink all the nice goodness. But i dont know if thats a good thing or bad to be honest.

I am only a newbie myself, so maybe some of the more experienced guys could give us both some advice.

ok so you have holes in the bottom of the cups right....well if you can see roots threw the holes you know its time to transplant i dont like transplanting before i see root all the way to the bottom because the soil can fall apart and cause more stress on your little girl then it needs.

You will be able to see a root system in the soil like previously stated. I try and transplant when soil is really dry that way when I transplant I can give it a good watering and make the roots stretch out to ensure it took ok. Ive never had a problem doing it this way. Cut the cups down the sides and across the bottom so the cup falls into two pieces without disturbing your root systems growing and little soil falls away. Fill the new potter with its soil and use one of your EMPTY cups to make a transplant spot in soil for a easy fit. put 1-2 inches of soil on top after transplant. then good watering. I transplant strait to 5 gallon bucket.