Material
Potting mix
Give a seedling a growing medium with space for roots, air, and water.
Get to know it
Choose a packaged potting mix suited to the plant. Garden soil can compact in small containers. Moisten the mix before planting; it should be damp without becoming a waterlogged mass.
Container roots need drainage and air as well as water. A gravel layer does not fix poor drainage. Match the pot to the plant and move a growing seedling to a larger suitable container when needed.