Fill the pot to within one inch of the rim with moistened soil. Use a 6-inch-diameter pot per sprout if you are planning to transplant the cabbage to a garden bed later. Use a 1-gallon pot for sprouts you are growing to maturity inside the container.
Scoop the cabbage sprout from the seedling tray using a clean spoon. Insert the spoon deep enough into the soil so you scoop up the roots without cutting through them or damaging them.
Make a hole in the soil surface inside the new pot with your fingers. Ensure the hole is the same depth and slightly wider than the root system on the sprout.
Place the sprout in the planting hole. Handle the sprout by its topmost leaves when moving and potting it to avoid crushing the stem. Sprouts grow back leaves, but a crushed stem kills the seedling.
Tamp the soil around the roots lightly in place with your fingertips. Keep the pot in a warm, sunny location. Water 6-inch pots when the top of the soil feels dry and water gallon-size pots when the top inch of soil dries.