February 7, 2001
Stillwater Gazette
Betsy Halden

Repotting your houseplants

On my sunny kitchen windowsill I have a lovely fern that has grown well for over a year. As I lifted it out of its saucer this week I saw roots growing out of the bottom of the pot. The same was true for the hoya and the rosemary plants. Time for action.

Repotting houseplants is a great wintertime activity. It satisfies gardeners who are itching to get their thumbs dirty. But not all houseplants need to be repotted. There are several indicators to help you decide if you need to find a new pot for your plant.

The main reason for repotting is to give the plant’s roots more room to grow. One of the most obvious signs that repotting is needed is when the plant is physically too large for the pot. Overgrown plants in plastic pots are prone to tipping over as the soil dries. Roots may begin to grow out of the drainage holes in the bottom of the pot. These are red flags that the plant probably needed repotting several months ago.

A quick method to determine if the plant has outgrown the pot is to turn the pot over. Gently pull the plant out of the pot, and examine the soil ball. If many roots are visible at the outside of the soil ball, the plant probably needs a new pot. If roots are not visible, repotting is not needed.

When selecting a new container, choose a pot one size larger. If the pot is too big for the plant, the soil will tend to stay excessively moist for too long. This can lead to root rot. As you fill the new pot with soil, be sure you leave enough room at the top to allow for watering.

In some cases, some plants may already too large for the environment in which they are growing. They would only continue to grow larger if they were placed in a larger pot. These plants should be repotted, replanted in fresh potting soil in the same size container.

Timely tip: Our recent ice and slush storm left many trees and shrubs covered with heavy wet slushy ice. Whenever ice coats plants and trees, it is best not to disturb the branches. The limbs or branches could break under the weight of the ice. Allow the ice to fall off or melt.

If you have wondered about the effects of cold and snow on our gardens, you may find helpful an excellent new fact sheet from the British Columbia Ministry of Agriculture titled “The Cold Facts About Winter.” The publication describes eight types of winter injury that can occur to plants. It also discusses the effects of moisture and nutrition on winter hardiness of plants. The fact sheet is available on the Internet at www.agf.gov.bc.ca/croplive/plant/horticult/nursery/winter.pdf.

Betsy Halden is a Master Gardener with the University of Minnesota Extension Service. University of Minnesota Extension Service materials were consulted in the preparation of this column. You can reach Betsy Halden at eahalden@comcast.net