By Rob Proctor, Gardening Expert
Thursday, July 27, 2007

This time of year, gardeners watch the weather forecasts diligently, dreading the first time temperatures drop below freezing.

On that fateful night, there are a number of tasks to get done before you go to bed. Prepare now for the first frost.

The good news is that a light frost won’t likely damage most perennials, grasses or shrubs such as roses. The vulnerable plants include tender annuals, vegetables and tropical plants. I usually rush out and harvest remaining tomatoes, peppers and eggplant. For tomatoes, get as much stem as you can, spread them on newspapers and they’ll ripen nicely indoors.

Often we have one isolated frost and then several weeks of warm weather. if you’re an optimist, cover your vegetables with sheets and they may continue to produce. I also use sheets and towels to protect container plants. To keep the weight of the fabric from breaking the plants, use bamboo stakes to support the sheets. Then secure them with chip clips and clothespins in case it’s windy. Use rocks or bricks to hold the sheets down on the ground. Of course, lightweight pots can be moved to the safety of the garage or porch.

Eventually you’ll want to decide which potted plants get saved for the winter. Here’s some help in deciding:

Bulbous plants such as cannas, dahlias, gladiolus, tuberous begonias, and pineapple lilies can be allowed to frost. Cut off the dead foliage, dig up the bulbs and store them in a dark, cool spot such as a corner of the basement.

Annual plants fare badly indoors. Petunias, marigolds, flowering tobacco, impatiens and zinnias should be allowed to freeze.

Most tropical plants are worth saving. You don’t need a greenhouse, just some window space. Consider rescuing potted foliage plants such as palms, ferns, dracaenas, dwarf bananas, New Zealand flax, philodendrons and spider plants as well as cactus and succulents. Blooming tropicals that can be housed inside include bougainvillea, angel trumpets, mandevilla, blue potato tree, gardenia, agapanthus, kangaroo paws, hibiscus, lantana and non-tuberous begonias such as ‘Red Dragon.’

And what about those pretty pots of coleus and geraniums? Save them if you have room. If not, take cuttings of your favorites and grow them on your windowsill. Make cuttings about 6 to 8 inches long. Remove all the bottom leaves as well as flowers or buds. You can root them in water or insert them into fresh, clean potting soil and firm the soil around the stem. Water them and place a clear plastic bag over the cutting, securing it with a rubber band around the rim of the pot. This makes a temporary miniature greenhouse that helps them to root. After a few weeks, tug at the stem gently. If it resists, the cutting has formed roots. Remove the plastic bag and enjoy your new plant, which can carry on next spring on your patio.

(Reprint of KUSA*TV article, All Rights Reserved)