If a plant’s roots protrude from the drainage holes, if it wilts between normal waterings, or if there’s little new growth, it may be time to repot. In general, young plants need repotting every year: older ones, every 2 to 3 years. Repot at the start of the growing season, usually in early spring.
Water a plant thoroughly 1 or 2 hours before repotting it. To remove a plant from a small or medium pat, put one hand, palm down, on the soil. with the plant’s main stem between two fingers, Invert the pot and tap its rim on a table edge a few times to loosen the root ball. Lay a larger pot on its side, and turn it slowly, tapping its rim gently with a wooden block or mallet. If necessary, stand the pot up-right and run a knife around the in-side of the rim. Hold the main stem while an assistant pulls the pot away.
If the root ball shows mostly potting mixture, leave it in the same pot. If it’s covered with roots, move it into a well-scrubbed pot, 1 to 2 inches larger in diameter. Before using a new clay pot, soak it in water for 5 minutes. Cover the drainage hole with a few clay-pot fragments; cover the fragments with sheet mass or a few dry leaves. Add a 1- to 2-inch layer of fresh, moist potting mixture and tap it down.
Center the root ball in the new pot; the top of the ball should be 1/2 to 1 inch below the pot rim. Pour fresh potting mixture around, but not on top of, the root ball. While filling the pot, tap it repeatedly on a hard surface. Firm the mixture gently with your fingers or pack it with a stick, then water thoroughly. If a plant is too large to repot, top-dress it every year or two. Scoop out the top 2 inches of soil without exposing major roots. Refill the pot to its original level with fresh mixture.