How can you tell when your plant needs repotting? If the plant requires water more frequently than before, if it looks top heavy in its container, or if roots are growing out of the drainage holes, your house plant may need to be transplanted into the next size pot. However, the best way to check is to look at the root ball.
STEP 1: Remove the plant from its old container by spreading your fingers over the surface of the soil and turning the plant upside down. Larger plants can be placed on their sides and pulled gently from their pots. If the root ball does not drop into your hand or slide out easily, tap the sides and bottom of the pot to loosen the soil. A plant that is extremely pot-bound may require that you run a long thin knife blade around the inside of the pot to loosen the grip of the outer roots on the container. Sometimes you have to simply break or cut the pot off.
Examine the root system to determine if a larger pot is indeed necessary. Most plants do not require a larger container until they have filled most of the outer area of the soil ball with roots.
STEP 2: Select a new container that is slightly deeper than and about one inch larger in diameter than the plant’s root ball. Too large a container does not stimulate any more root development than a pot that is just one size up, and it can increase the dangers of over-watering.
The container may be plastic, clay, or other material that will hold the soil in place. The advantage to clay is that the soil can dry quickly (for some plants too quickly) and evenly. Plastic pots will keep the plant wet longer, but are light weight, and easy to clean. Decorative containers like glazed ceramic pots are attractive and will retard drying, but are heavier and more easily damaged. Choose a container that’s appropriate to the location it will be in and that works with your style of watering.
Place broken clay or pieces of window screen over the drainage holes to keep the soil from washing out. Containers without drainage holes are not recommended; however, if used, be sure to put ample drainage material in the bottom.
STEP 3: Gently loosen the outer roots with your fingers so that they can grow into the new soil. A very tightly matted root ball can be scored in several places and across the bottom with a sharp knife or razor blade to get you started. Also trim off any dead roots (dark brown or mushy).
Place a small layer of potting medium in the bottom of the new pot. If using a peat-based potting mix, dampen it lightly before potting. Set the root ball in the pot and fill in the space around it with more potting medium, firming gently as you fill. Do not add potting medium to the top of the root ball unless you are replacing medium lost during transplanting—always plant at the original soil level. If the plant is sitting too low in the pot, pull it out, add more medium to the bottom of the pot, and fill in the soil again. Do not pot the plant so high in the container that you cannot water it.
STEP 4: Water gently and thoroughly to settle the new potting medium, adding additional medium as needed. Let your plant settle in to its new container by keeping it in bright diffused light. It will probably require less frequent watering, and should not be fertilized until the plant begins to grow actively again.
NOTE: If you use a container that has no drainage holes (dish garden, crock, etc.), you need to make sure that the plant’s roots do not stand in water. The best way to accomplish this is to water the soil thoroughly, then tilt the container on its side (use your hand or paper towels to keep the soil in place) and let the excess water run out.