Things You'll Need
Perlite or vermiculite
With an intoxicating scent, white flowers and glossy green leaves, gardenias are irresistible houseplants. A potted gardenia makes an attractive addition to patios, porches and other outdoor living areas where winters are mild and free of frost. When growing a gardenia in a pot, the plant will need repotting as the roots and the plant grow. Roots growing out of drainage holes or growing on the surface of the soil are good indications that its time to move up a size.
Replant the gardenia in a pot that is 1 to 2 inches larger than the current pot. Avoid larger pots, as the extra space around the roots can cause water to build up in the soil and damage the roots. Look for a pot that has several holes in the bottom to allow for water drainage.
Turn the gardenia on its side in the pot and, grasping the base of the stem with one hand, gently wiggle the pot away from the roots with the other hand.
Prune any roots that are twisted around the root ball or matted and twisted under the root ball. Make clean cuts when pruning gardenia roots, using sharp pruning shears.
Put 2 to 3 inches of potting soil in the bottom of the new pot. Use a sterile potting soil mix or make your own by combining equal parts sand, peat moss and vermiculite or perlite. Don't use garden soil, as it is too heavy for container culture.
Place the gardenia into the new pot, holding it so the base of the stem is 1/2 to 1 inch below the lip of the pot. Adjust the soil level in the bottom of the pot until the gardenia stands on its own at the correct height.
Put more potting soil around the root ball to fill the new pot to the base of the stem, leaving 1/2 to 1 inch between the soil line and the lip of the pot for easy watering and fertilizing.
Press down the soil gently with your finger tips. Soak the pot until the soil around the gardenia roots is thoroughly damp and water drains from the holes in the bottom. Place the pot in a sink or outside to drain.
Repot gardenias in the spring or summer when the plant is in its growth stage.