by Don Janssen, Extension Educator
By easing the plant out of the pot, you can view the roots.
The roots of this housplant are in a thick, tight mass so
it is easy to determine that it needs repotting,
Because plants need light to grow and the short days of winter don't provide much, houseplants generally do most of their growing in the summer. This makes fall a good time to check to see if they've outgrown their pots.
A common sign that plants need repotting is soil that dries out very quickly. Other indications are soil that seems to be more roots than soil and roots coming out of the drainage hole.
To find out for sure, water the plant, let it drain for a while, and then tip it out of its pot and examine the roots. To ease the plant out of its pot, tip the container on its side and rap the rim against a tabletop or bench to loosen the soil ball.
Soil covered with a thick, tightly matted mass of roots means the plant needs repotting into a bigger container. If very few roots are showing and those you do find are black, soft, slimy or otherwise unhealthy-looking, the plant has problems.
Rotten roots are usually related to overwatering. This can be related to the size of the container, the frequency of watering or the absence of a drainage hole in the container.
Plant roots need air as well as water. Plant roots that sit in saturated soil for long periods of time tend to rot and die.
To repot healthy plants, use a container no more than 1 to 2 inches larger in diameter than the previous one. Avoid planting into a greatly oversized container. Oversized pots often result in plants being overwatered. If the only choice is a slightly undersized pot or an overlarge one -- use the smaller one.
If the main reason for repotting is to counterbalance the weight of top growth that is making a small pot tippy, the pot that looks proportionally to the top of the plant may be too big for the roots. A solution is to repot the plant in a smaller container and set it inside the larger one.
This is a good approach when you want to use a decorative container but it doesn't have a drainage hole. Pot the plant in a container with a drainage hole and set that on a layer of gravel inside the other.
To repot, start with a clean container. Add a few pebbles, shards of broken clay pot or a piece of nylon screen in the bottom of the container to keep soil from washing out the drainage hole, if you like. Then add a little potting soil and set the plant in the new container and fill in around the root ball. Water to settle the potting mix and add more, if necessary. For room to water without overflowing the pot, make sure the soil surface is 1/2 inch or so below the rim.
Most of the problems that people have with houseplants in the winter are related to watering. Potting plants only in containers with drainage holes and making sure the soil around the roots is dry before you water will go a long way toward keeping plants healthy over the winter.
University of Nebraska-Lincoln Extension in Lancaster County is your on-line yard and garden educational resource. The information on this Web site is valid for residents of southeastern Nebraska. It may or may not apply in your area. If you live outside southeastern Nebraska, visit your local Extension office