The gardenia (Gardenia jasminoides) is a tropical flowering plant and a relative of the coffee plant. Gardenias thrive in areas with evening temperatures near 60 degrees F, warm daytime temperatures and high humidity. Grown in containers, gardenias require extra care, and bloom best when pot-bound. The plant is intolerant of root disturbance, so transplanting must be done quickly and gently. Transplant the gardenia when roots begin growing from the bottom of the pot.
Fill the new planting pot half-full with potting soil that's rich in peat moss. Water it until the water drains from the bottom of the pot.
Tip the gardenia plant out of its pot and place it into the new pot so it sits at the same depth as it was in the old pot. Add or remove soil from the pot to adjust the plant to the correct planting depth.
Add a handful of soil to cover the roots and 1/2 cup of water. Gently work the soil around the roots with your fingers. Disturb the roots as little as possible.
Fill the pot the rest of the way with soil. Water the plant until the water drains from the bottom of the pot. If the soil settles, add more until it is within 1/2 inch of the rim of the pot.
Fertilize the gardenia three weeks after transplanting. Use a 30-10-10 formula at the rate suggested on the package for your pot size. Always water after fertilizing.