When does a plant need repotting? Any time its roots are overcrowded in the container. But don’t wait for outward signs that a plant needs repotting The following clues tell you it’s time to repot:
You see lots of roots coming through the drain hole.
You find matted roots near the soil surface.
You slip the plant from its container and you see more roots than soil.
Poor flowering, quickly dried out soil, stunted leaves and stems, and even leaf drop and die-back are signs of distress. Plants give these signals because they’re not able to draw enough nutrients and moisture from their current root situation. Check container plants regularly, if possible, slipping them out of their pots to examine the roots for crowding.
Annual flowers and vegetables that you’ve started from seed in small containers need frequent repotting into progressively larger containers, perhaps as often as every month, until they’re ready for their season-long home, which should be a container chosen to accommodate their mature size. Ditto for young transplants that you purchase.
Permanent plants, such as trees, shrubs, and perennial flowers, may need repotting every few years. Permanent plants are best repotted when growth is slow or when they’re dormant, either before or after flowering. With this schedule, plants have a chance to recover from the root disturbance that invariably occurs during repotting, no matter how careful you are. Repot spring-blooming permanent plants in fall and evergreens in spring or fall.
