Early spring is the ideal season for repotting houseplants. That’s because plants just beginning a new growth cycle (the case in early spring) are less jostled by transplanting then plants in full growth (late spring though mid-autumn). And less likely to rot than plants repotted in winter. But why do it at all? Here are some of the reasons:
First, plants that grow in the ground have no restrictions on their root growth: they can send their roots deeper and deeper and farther and farther in search of water and minerals. Houseplants don’t have this advantage. Without an occasional repotting, the development of the roots will be severely restricted… and if the roots stop growing, the green parts of the plant will also slow down or stop. And flowering as well.
Moreover, because we water houseplants in a “closed loop system” (any excess water remains in the saucer and is reabsorbed by the plant rather than draining away into the ground as it would in nature), their potting soil slowly becomes contaminated with toxic minerals. Also, soil ingredients deteriorate with time: peat and bark particles decompose, perlite and vermiculite compact down, etc. This reduces the flow of air to the roots, which, again, slows the growth of the plant. And lack of air circulation to the roots can even lead to rot.
Finally, when the available potting mix is full of roots, it can no longer fulfill its role as a water reservoir and then the plant begins to wilt too quickly between waterings, starved for moisture, forcing you to water 2 or more times a week.
For all these reasons, repotting your houseplants every now and then is worthwhile.