Repotting is an important part of keeping healthy houseplants. The best time of year to repot is in spring, before the new flush of summer growth. Here are signs you need to repot:
- Roots protruding from the bottom of the pot
- The plant stops growing or becomes limp
- The plant is root bound
Remember, however, that many tropical plants like to be slightly under-potted, and unless you need to repot because the soil is exhausted or the plant is suffering, there's no reason to do it early. An over-potted plant will focus on root growth at the expense of new foliage and flowers. Finally, some plants, such as bromeliads, will almost never need to be repotted. If a bromeliad sends out pups, or mini-plants, just cut these off near the base of the mother plant and pot them up separately.
If you decide that a plant does indeed need to repotted, follow these steps:
- Remove the plant from the pot. Lightly water the plant, let it dry for an hour or so, and then gently remove the plant from the pot. You can do this by turning the pot over and gently pulling the pot up and away from the root ball. It's not a good idea to yank a plant out of its pot by the stem.
- Prep the root ball. It's OK to gently loosen the root ball with a finger or a fork, but be careful not to cause any root damage. Cut away dead or rotted roots. If you plan on repotting the plant into the same size pot, see How to Root Prune Your Plant.
- Prepare the new pot. In general, you should only repot a plant up one size of pot. In other words, you can move from a four-inch to a six-inch pot, but not a four-inch to an eight-inch pot. This will slow growth. Plastic or ceramic pots are fine, depending on your preference. Add fresh potting soil directly to the pot. Many of us were taught to first add pebbles or some other drainage media to the bottom of the pot first. In reality, however, this reduces the growing area for the roots and actually hastens decline of the potting soil by paradoxically reducing aeration.
- Planting. Gently set the new plant in its new pot and backfill with soil or compost. One of the main causes of plant collapse is planting too deep. Make sure the newly potted plant isn't planted deeper than it was in the original pot. As you're filling in, press the soil down firmly and tap the pot gently to settle all the dirt.
- Water. Water thoroughly, and if necessary, add a little more soil to top it off. You should water until liquid seeps from the drainage holes at the bottom of the pot.
If a plant is too large to repot, you can top dress the soil by carefully removing the top few inches of soil and replacing it with new compost.
Finally, a word about fertilizing newly repotted plants. Most store-bought compost mixes have fertilizer included. In general, you shouldn't fertilize newly repotted plants for six weeks. This will reduce the chances of burning the new root growth.