Sooner or later your seedlings overgrow their little containers. My Tumbling Tom seedlings were already outgrowing their starter containers and they were moved to large container to ensure that they had space to grow. I used a trellis from the Dollar Store with twines to hold the seedlings in place. I mixed sheep manure and potting soil (1:1) prior to transplanting, then watered the seedlings thereafter. Basil and Nasturtium flower seedlings were added to the planter to act as companion plants for the tomatoes to deter pests and diseases and keep the plants healthy.
Spinach, coriander, small peppers, Mescuin salad mix and all the other seedlings were moved into larger containers. Herbs such as basil, thyme and oregano requires smaller containers.