Overwintering Tender Plants Indoors

Looking to save a little money on plants next spring? Have a plant that is special to you? Finally found the perfect shade of pink annual plant and want to keep it for next year? Now is the time to take action- bring your plants indoors before the cold weather returns by following a few easy tips!

"Tender perennials, which are usually plants that gardeners in the colder regions consider annuals, are easily overwintered indoors, caring for them as you would any houseplant," said Brittnay Haag, University of Illinois Extension Horticulture Educator. Examples of these tender perennial plants are: geranium, coleus, lantana, begonia, Persian shield, and Joseph's coat.

Plants can either be overwintered by digging up the entire plant or propagating the original plant. Whichever method, it must be done before the threat of the first frost.

If the plant is small enough, or you have ample room, the entire plant can be dug up and planted in a container of fresh potting soil. Make sure to get as much of the root system as possible to cause less stress to the plant. Cut back the plant so a half of the original plant is remaining.

Some plants can be easily propagated to start multiple new plants. Tips cuttings are taken by selecting a healthy, 3 to 5-inch shoot with four to six leaf nodes, and cutting below a leaf node. Remove any flowers or buds, and the bottom two to four leaves. Insert the lower portion of the cutting into a container of moist potting soil and water well. Cover the entire container with a clear plastic bag to keep the moisture level high around the plant. Place the container in bright, indirect light. Roots should form in three to four weeks, when you can remove the plastic cover.

Steps for overwintering plants indoors:

1. Look over each plant carefully for signs of pests and diseases. Rise off leaves with water to be sure no tiny bugs are hiding. Only bring healthy plants inside.
2. Either dig up the entire plant and replant in fresh potting soil, or take cuttings as described above.
3. Place plants in a sunny location. Supplemental lights can be used if there is not adequate natural light.
4. Water the plants when the top inch of soil becomes dry. Water each container until it flows out of the bottom drainage holes.
5. To increase the humidity around the plants, place a shallow pan of gravel and water under the pots.
6. Plants will not need to be fertilized during the winter because they are not actively growing.
7. Gradually acclimate plants to outside weather again (harden off), by setting them outside during the day once day temperatures are over 60°F. Plants can be placed outside full time once the threat of frost has passed.

Tropical plants such as, cordyline, gardenia, and croton, as well as some herbs, like sage, rosemary and bay can also be overwintered by bringing them indoors before the first frost.

As with all gardening, the process of overwintering tender perennials is trial and error. You may find that some plants are easier than others to overwinter in your home. Keep your thumb green all winter by caring for your garden plants and possibly saving a few bucks in the spring.