Once the roots have reached the edges of the sprout container, it is ready to either move to a bigger pot, bed, or ground. We start our seeds in peat pods or pots so the whole plant can be planted into the soil. However, if you are using plastic pots, you will need to squeeze the sides of the pot until the soil and roots move away from the inside edges. Support the stem and roots as you turn the plant on its side to remove the pot. If the roots have been circling the pot, you will need to gentle massage them away from the root ball.
All you need to do is move the soil with your hands and place the plant inside the hole. Firmly push down around the roots to ensure that you remove air pockets. If the soil is too loose, the plants may not survive.
When you are planting tomato sprouts, experienced gardeners prune the lower suckers and plant the lower stem of the sprout underground. Roots will grow from the part of the stem buried underground. This method encourages a strong root base when the plant is being established. It will help the tomato plant to grow stronger in the long run. If you happen to save the suckers, you can use these cuttings to make extra copies of this plant.