Now that your seedling are up, time to give the roots some more room to grow. Simple instructions for "potting up" tomato seedlings into larger containers.
What you will need:
balanced fertilizer or fertilizer included in your potting mix
paper pots, cow pots, plastic pots, or larger soil blocker (1 1/2" or 2")
seedlings with at least 1 set of "true" leaves, not the two little cotyledons (seed leaves) that first emerges from the seed, the next set of "true" leaves.