Repotting Houseplants

indoors at a botanical garden with blue planted containers with green plants and colorful flowers

The months of March and April are often difficult for gardeners, who wait patiently all winter for the chance to start planting outdoors. It has been especially difficult this year with the unseasonably warm winter. One way to scratch the gardening itch is to prepare your houseplants for the coming season! March is a good time to repot houseplants to prevent them from becoming rootbound. If a plant is rootbound, it will have a lot of roots circling around the outside of the soil or coming out the drainage holes. These roots are not effectively taking up water or nutrients because they aren’t surrounded by soil.

The first step is to determine if a plant needs to be repotted is to remove the container. It is tempting to pull on the plant to remove it, but this can lead to damage on the stem or loosening the roots from the soil. Instead, place your hand around the stem (or between the stems) and turn the pot upside down. If it does not slide loose, give it a quick vertical shake or firmly tap the bottom of the pot until it loosens. Then, examine the roots. If the roots are brown or wrapping around the edge of the soil, it is time to repot!

The next step is to gather supplies. A new pot that is roughly 1-2” larger in diameter is ideal, it allows the roots room to grow, but does not hold excessive moisture. The new pot should have drainage holes in the bottom. If it does not, it is considered an ornamental pot, and it is strongly recommended that the plant is repotted into a thin plastic pot and this plastic pot is placed into the ornamental pot. Next, find the appropriate potting mix. Some houseplants have a specific potting mix made for them – like African Violets or Orchids – but most will do well with a generic potting mix which includes peat, composted bark, and perlite. Once these materials are gathered, it is time to move on to the next step.

Once again, remove the plant from its pot. Loosen the roots by lightly massaging the soil. If the roots are very dense and won’t come loose, use a knife to cut a vertical sliver off of the root mass to encourage new root growth in that area. If the new pot is deeper than the old pot, add soil to the bottom of the new pot until the plant’s soil line is even to or slightly below the pot’s edge. Fill in around the edge of the plant until you hit the soil line, and then slowly add water to the new potting mix until it settles. Add more potting mix and water until the potting mix is even with the existing soil line, but do not bury the existing soil line or crowd the stem of the plant. Packing the new soil down reduces aeration and increases the chance of root rot, but can be done with top-heavy plants to keep them from leaning. Finally, water the entire pot and place it back to its original position. Avoid fertilizing repotted plants for at least two weeks, but feel free to spray them with a gentle insecticidal soap if you notice any problems.