THE INDOOR GARDENER : Tips on How to Winterize Your Houseplants

Winter is a-comin’ in--and that means it’s time to “winterize” your houseplants.

We in Southern California tend to scoff at the idea of “winter,” but our houseplants take this season from November through March very seriously. Shorter days, little or no sunlight, colder nights and much less humidity in our homes make life difficult for almost all our indoor foliage and flowering plants.

Here are some tips to help you get your little green companions through these upcoming dreary days.

Bring all plants indoors that have been outside on summer vacation. Because these plants have surely grown considerably over the past months and because there’s no telling what types of pests may have settled on the foliage or invaded the soil, now’s a good time to clean and repot them. This also applies to any plants that have remained indoors but have been situated near an open window.

If you want a plant to go back into the same pot, discard the old soil and scrub the pot with hot, soapy water to eliminate all pests. Cut back about one-quarter of the roots (no, this will not hurt or shock the plant) with sharp scissors and then repot it in fresh, sterilized commercial potting mix.

If you want a plant to get larger when it starts growing again in the spring, leave the roots alone and repot the plant into a container no more than 2 or 3 inches larger than its old one.

For those big trees in large pots such as palms and dracaenas, scoop away the top couple inches of old soil, aerate the top of the remaining soil with a hand-rake or a fork, then add a couple of inches of fresh soil to replace the old.

Clean your plants thoroughly to get off all the dust and dirt that’s bound to have accumulated on the leaves whether the plants have been outside or in. If they’ve been outside, bathe them with a fine spray from your garden hose and then, as a final safety precaution against pests, spray them with a commercial insecticidal soap according to package directions.

As for the plants that have gathered summer dust indoors, spray them with a solution of one part mild dishwashing soap and 10 parts water, then spray with clear water, then wipe the leaves with a sponge or a soft paper towel. A clean plant is much more likely to be a healthy plant and will have a much better chance to survive the rigors of winter with minimal problems.

Cut back vining plants such as wandering Jew, creeping Charlie or Swedish ivy. It’s likely that these plants have grown straggly during the summer months, and a good haircut will energize then for a robust re-burgeoning come spring. Flowering plants such as azaleas and hibiscus should be pruned back now too.

Lack of humidity is a big problem in winter. What with most of us having to use our heaters at least at night, your plants can suffer greatly.

I’d suggest you get a couple of inexpensive humidifiers--one to put in the room where most of your plants reside, and the other in your own bedroom. This extra humidity is very beneficial both to the well-being of your plants and you.

If you don’t want to invest in humidifiers, remember that even though your plants are dormant and not growing, they still need a regular misting to keep the tips from drying up. Try to travel around your “plant-tation” with a spray bottle at least three or four times a week. And be sure to keep your plants away from any direct exposure to dry heat.

Lack of light can be something of a problem during the winter months, especially for flowering plants such as African violets and those cactus and succulents that need lots of sunshine to do their best. If your violets stop blooming for a couple of months during the winters, fear not. It’s simply a lack of light and they’ll begin blooming again as the days grow longer and brighter.

As for the cacti and succulents, the fact that the plants are dormant compensates greatly for the lack of light and they’ll make it through the winter with very little wear and tear.

By the way, one of the great rewards of growing cactus is seeing those fabulous cactus flowers appear in spring, and the way to ensure your cactus will bloom is to take advantage of the chilly winter nights. The “secret”: If possible, put your cactus plants in a place that gets really cold at night. The cold helps trigger a chemical reaction that will usually result in spring blooms. Most cacti and succulents will withstand temperatures as low as 30 degrees.

Cut back on watering and cut out feeding your houseplants during the winter. You’ll have to water once in a while, but be sure and wait until your plant’s soil has dried out completely before you water during this period.

With the exception of certain flowering plants whose normal growing season is winter, such as cyclamen, don’t feed your plants during their dormant months. Begin a normal fertilizing regimen--every other week with a good liquid houseplant fertilizer--around the first of April.