The Iowa Gardener: Get a head start on spring and overwinter some plants

The first frost is here so now is the time to act to save some of your favorite plants to enjoy indoors through the winter.

Plants in pots

If you have any annuals or other plants in pots that are still healthy and attractive, consider bringing them indoors to enjoy for a few more days to several weeks. Most plants that thrive outside don’t get enough light inside, but will do OK for a while.

Start by hosing off the entire plant to get rid of any insects and dirt. Wipe down the pot and put indoors in the sunniest spot you can. Keep moist. When leaves start to yellow or drop, it’s time to say goodbye to that plant. Put in your trash or compost heap.

Plants from cuttings

Some annuals will root easily in water. Take cuttings now, before the weather gets any colder, so they will last for a few more months and maybe even until spring.

Basil, begonias, coleus, ivies and more root beautifully in a jar of water in a window. I’ve even had luck with impatiens. Experiment with your favorites.

Once the roots are about an inch long, pot them up in potting soil. Many will thrive if you have a sunny, south-facing window. Otherwise, if you’re really determined, put them under a grow light. With a little luck, you’ll be able to save them so that you can replant them outdoors in spring after the last frost (usually early to mid-May).

Rosemary

In warmer climates, rosemary is a true perennial and in the southern United States it even grows into a small shrub. In Iowa, our winters usually (but not always) kill it. I like to dig it up in fall, put it into a pot with potting soil and keep it on a sunny windowsill.

Too often, my furnace makes the air in my house too dry and the needlelike leaves will brown and drop, and I end up pitching it in January or so. But some years, it lasts until spring and I can plant it outside again.

Helpful tip: If you plan on bringing your rosemary indoors in fall, plant it in a large pot and sink the pot into the ground and surround it by soil. That way, in spring, you can just lift the whole pot, clean it off, and bring it inside with minimal fuss and without disturbing the roots.

Geraniums

Dig or pull up your geraniums, knocking as much dirt as possible off the roots. Remove any dead or diseased leaves and stems. Put them upside down in a cardboard box and loosely close the lid to allow for air circulation. Keep it in a cool — 50 degrees or 60 degrees — space that is also dry (not a damp basement).

Check once or twice during winter and pull out moldy plants. In March or so, remove the remaining geraniums. Cut back the brown stems until you see some green in the center. Plant in pots of potting soil and water only very lightly. Put in a sunny spot indoors. Don’t water again for another two to three weeks. Then water often enough to keep the soil lightly moist. Plant outside in early to mid-May, after the last frost date.

Some people simply pull up and pot their geraniums in the fall, letting them overwinter in a sunny spot or under a grow light. Experiment to find out which method you prefer.

Veronica Lorson Fowler is co-publisher of The Iowa Gardener website at theiowagardener.com.