It’s Time to Repot your Houseplant When…
…The plant begins to wilt only 2 or 3 days after you last watered it. That’s because its root system is so developed it has no more room to expand, plus the empty space between soil particles that normally serves as a water reservoir is now totally filled in. Think about it: if you repot your plant into a larger pot, you won’t have to water so often!
…The plant keeps tipping over. It’s become top heavy and will need more potting mix to hold it up. You might want to consider using a heavier mix (like cactus potting soil) or a heavier pot: clay and ceramic pots are heavier than most plastic ones.
…A whitish or yellowish crust has formed on the edges of the pot and the base of the plant. These are toxic mineral salts that build up over time in the soil of houseplants. By the time they are visible, they have started to kill the plant’s roots and may even be eating away at its crown. It’s best to repot and to remove as much of the contaminated old soil as possible.
…Lots of roots are wandering out of the drainage holes. This is a clear sign that the roots are looking for more space. Give them some!
…Root pressure has cracked the pot or even split it open. Idem.
…Spring has arrived! It’s simply a good idea to repot your houseplants regularly. Do so every spring for small to medium-sized plants and every two springs for large ones. Regular repotting helps maintain healthy growth and good bloom.
But I Can’t Repot My Plant!
Maybe it’s simply too big or unwieldy, making repotting difficult. If so, at least do an annual top-dressing. You’ll find all the details here.
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. And tomorrow we’ll look at how to do it!