If it's spring, it's time to repot houseplants. "It's one of my least favorite gardening chores," says master gardener Paul James. "There are so many other gardening chores to do. But after being cooped up for months under less than ideal conditions, including dry air, excessive dust, drafts, low light levels and even pollution from all sorts of household products, my houseplants are ready for a little rejuvenation."
Plus, if houseplants aren't repotted, they may eventually suffer because their root systems can grow so large that they may not be able to derive the water and nutrients needed to support the top growth. When that happens, plants tend to become stunted, and older leaves may lose their color and drop.
Why repot in the spring? Plant roots grow most actively in the spring, which means the plant will be able to quickly overcome the shock associated with repotting.
Repotting steps:
- Water your plants well three or four days before repotting. Since repotting is a messy job, you might consider tackling the task outdoors. Just make sure the weather is warm enough --in the 60s--or the plant may go into shock.
- Invert the pot and gently remove the plant by grasping the main stem. Give it a slight tug, and it should slip out of the pot. If it doesn't, use a butter knife or other flat-bladed tool to loosen the sides of the pot and try again.
- If you want the plant to grow larger, then you will need to repot it in a larger pot. If you want it to maintain its present size, you'll have to prune its roots.
- Add some fresh potting soil to the new pot, packing it well around the drainage hole. Then transfer the plant to the new pot. Adjust the amount of soil mix needed so that the plant is at the same level as it was in the old pot. Position the plant, then add soil mix to fill, and water well.
You can use this same procedure to pot plants of any size; just make sure that the new pot is only slightly larger--no more than an inch or two in diameter--than the old pot. Most houseplants don't respond well to being moved from a small pot to a much larger one. - To root-trim a houseplant, simply trim the outer inch or two of roots with a sharp pruner, and place the plant in its original container. Add fresh soil mix to fill the pot and water well.
You might also consider pruning the top growth a little so that it is in proportion with the newly downsized root system. Keep in mind, though, that not all plants take well to this method. Avoid pruning top growth on cacti and other succulents, ferns and other plants that send up leaves directly from the soil line, peace lilies and Norfork Island pines. - If you have houseplants that are simply too large to repot, such as a big banana tree or a sago palm, your best bet is to top-dress them with fresh potting mix. Begin by removing the top inch or two of soil mix. Be careful not to damage too many of the surface roots. Apply a fresh layer of soil mix, packing it gently as you go, and water well.
- After a plant has been repotted or top-dressed, it may show signs of stress--the most obvious sign is wilting. It's a good idea to keep the plant out of strong light for a week or so to give it a chance to rest and rebound.
Not all houseplants need to be repotted every year. Some can go for several years without being repotted if they're top-dressed at least once a year; however, says James, "you'll notice a huge difference in overall houseplant health if you'll take the time to repot them once a year."