Showering With Your Schefflera

Indoor gardening can introduce a wide array of benefits into your home and office, from decoration and fragrance, to fresh-cut culinary herbs. Unfortunately, indoor plants can also introduce annoying pests and other unforeseen problems, especially if some of those plants were brought indoors to overwinter.

There is nothing more disheartening for the indoor gardener than to see a swarm of whiteflies hovering around a prized plant, or to see the tell-tale webbing of minuscule spider mites on curled, yellow foliage.

The first step to ensuring plant health, especially with plants you have brought in from the cold, is sanitation. Take each pot and check it thoroughly for hiding varmints. If the entire rootmass can be slipped out of the pot intact -- soil, roots, and all -- remove it and look for stowaway insects, like grubs, slugs, or ants. Use a soft brush and hot water and clean the outside and bottom of the pot. This helps remove any eggs or egg cases, as well as mold.

Using sharp scissors or pruning shears, remove any dead or dying vegetation, cut off fading flowers. Make sure that nothing is laying atop the soil surface, like old leaves, twigs, or other organic matter. These materials can harbor insect pests and eggs.

Next, in your sink or shower, depending on the size of the plant, spray down all the foliage, especially the underside of leaves, to rinse off any potential insects. You may want to repeat this step every month. Remember that rain not only waters plants, but also cleans off dust and other pollutants. To compensate, you can provide a nice, warm shower.

In fact, mimicking Mother Nature is the real key to maintaining healthy indoor plants. While nature provides outdoor plants with rain and breezes, humidity, light, and beneficial insects to help keep pests in check, that job is all yours indoors.

Another safe practice is to quarantine any new plant arrivals from your regular indoor plant population for a couple of weeks. Think of it as a horticultural Ellis Island.

Matching indoor plants with an appropriate location requires some research. Each plant has specific exposure needs. For example, diffused-light plants can become scorched in a sunny window, while sun-lovers will languish, and may perish, in a dark corner. Do not try to force a plant into the wrong space. You will find that as the plant’s health declines, the likelihood of a pest problem will increase dramatically.

With very few exceptions, most plant problems emerge from overfeeding and overwatering. During the winter months, plants should almost never be fertilized, and watering should be kept to a minimum. In addition, overwintering plants also typically prefer cooler temperatures. Check with a plant guide for specific instructions. Lanky plants sitting around with soggy potting soil are prime candidates for pest infestations, especially pesky fungus gnats and varied strains of mildew, all of which prefer damp soil conditions.

Dry, unmoving air is also a problem, especially for some larger foliage plants. If many of your plants are grouped together in a single room, you may find that a slowly revolving ceiling fan can help create enough of a “breeze” to keep pests at bay. Also, consider using a tray filled with damp gravel or pebbles under plants to raise the humidity to a healthy semi-tropical level. It is important, though, to rinse and clean those pebble-filled trays periodically, and generally never let any plant sit in a saucer filled with water. That situation is bad for the plant, good for pests, and can even lead to some unpleasant odors and airborne molds.

Despite your best efforts at sanitation, care and feeding, you may still encounter some pests. This does not make you a bad indoor gardener. However, you will have to take Mother Nature’s place and become a predator yourself, unless you really want to release several hundred ladybugs in your living room.

Fortunately, most pest problems can be managed safely and easily – and without toxic pesticides. The shower or rinsing method should certainly be a first line of attack, where feasible. The majority of insect pests hate water. Other approaches involve dipping or “soap baths,” which is akin to a whirlpool bath for smaller plants. For larger plants, spraying is the most effective approach, especially using some simple household products.

Dipping can take place in a bucket or a sink. Mix several teaspoons of mild dishwashing liquid with a gallon of warm water. Hold the rootball of the plant in the pot and dip all of the foliage and stems into the solution. Feel free to swirl the plant around, and dunk up and down. The agitation will help dislodge pests. Any remaining pests will find the soap covering their bodies hard to live with – and breathe through.

This same formula can be used in a spray bottle for larger plants. In both cases, you may want to repeat the process every week or so until there is no sign of infestation.

A more potent version of this soap spray calls for one teaspoon of soap mixed with a quart of warm water and several tablespoons of rubbing alcohol. The alcohol joins with the fatty acids of the soap to help penetrate the insect’s cuticle, ultimately dehydrating the bug. Never use alcohol by itself, as it can harm foliage, and on more tender plants, use a very dilute mix and test it on several leaves before spraying the entire plant. You can also use this mixture on a paper towel to wipe off leaves.

Powdery mildew, which frequently attaches itself to miniature roses and rosemary, can similarly be treated using a spray of warm water, several tablespoons of baking soda, and several tablespoons of dishwashing liquid, which serves as a wetting agent. Again, this treatment will need to be repeated periodically.

Other sprays and dips for special pests and applications can be created using garlic and onion, if you want to raid your pantry, mineral oil, and even safe, commercially-manufactured insecticidal soaps. You will find recipes for these formulations in most indoor plant guides and publications dedicated to organic gardening and integrated pest management.

Copyright 2009, Joseph M. Keyser