Store small cacti in clay dishes. After the cactus grow to a medium size, move them to pots. The size of the pot should be a bit larger than that of the root ball. It needs soil that remains moist but not wet. Always use a light soil mixture for cactus. Prepare a light soil mixture, using 2 parts of commercial soil and 1 part gravel and add perlite or any other soil amendment for good drainage. Sterilize this soil mix in an oven at 180º F for 30 minutes. When moving plants with thorns, make sure you wrap the thorny areas with paper to avoid any injuries.