It will soon be time to start bringing those indoor plants back in for the winter. You can save a lot of time and effort by getting some things done during this process. Here are some great tips to make that transition from inside to out.
Your plants will have to adapt to the different environment indoors of shorter days and dry, centrally-heated air. Consequently, water usage by your plant will change. Check the soil carefully for dryness before watering. If your home is hot and dry, you may need to water more frequently. If your home is cool in temperature and dim, your plants may retain moisture longer. For most houseplants, only fertilize during periods of active plant growth.
Most indoor plants slow their root and foliage growth during the winter months. If repotting your houseplant, choose a container that is only one-inch larger in diameter.
Check your plants carefully (both the leaves and the stems) for signs of plant pests. Even if you don’t see the insects themselves, check for telltale signs of damage, like chewed or stippled leaves, insect droppings, sticky leaves, or webbing. Try and treat the pest problems as best you can before you bring the plants inside.
Before bringing out the chemicals, try a few simple home remedies. For easily dislodged insects like aphids, crickets, daddy-longlegs, or spiders, try spraying them off with a stream or spray of water from a hose. Caterpillars and grasshoppers can be picked off by hand. Snails and slugs are usually active at night, so use a flashlight to catch them at work. Remove them by hand also.
Critters that have taken up residence in the soil can be removed by cleaning the root ball with a chlorine bleach drench (4 tablespoons of bleach per 1 gallon of water). Conversely, try submerging the entire root ball in a bucket of water for 30 minutes or more. Air-breathing insects like ants, pillbugs, centipedes, and more will either float to the surface or drown. Some can hold their breath longer than others.
Treat a mild infestation of mealybug or scale by removing any pests you see with a cotton swab dipped in rubbing alcohol. Treated plants should then be isolated and observed for signs of re-infestation, getting rid of any new pests until the entire population is eradicated. Damage to some fuzzy- or thin-leaved plants by contact with rubbing alcohol can happen, so test a leaf before treating the whole plant.
To control flying insects like fungus gnats and whitefly, agitate the plant while outside and then bring it quickly inside before the insects can settle on it again. For fungus gnat larvae in the soil, use the chlorine bleach drench mentioned above. If you see whitefly eggs, check the undersides of the leaves with a damp, soapy sponge to gently wipe away the eggs. For monitoring or control of flying pests, place yellow sticky bars (also called whitefly traps) near the plant.
For more massive infestations of mites, mealybug, scale, and other piercing/sucking insects, we recommend horticultural oil sprays. These should be applied outside in the shade and allowed to dry before bringing the plant inside. Be sure to read the label information for the best temperatures for optimal spraying. These refined oils are safe on most houseplants but would damage fuzzy-leaved plants like African Violets.
Another relatively safe product to use on houseplants is insecticidal soap. While some plants may show leaf discoloration, most houseplants do not. A soapy water bath is a great way to treat for mites on plants. Turn the plant upside down to swish the stems and leaves around in the suds. Pack paper towels around the base of the plant to contain the soil. Let the soap dry on the plant and protect the potting soil with paper towels to prevent soapy water from saturating the root ball, as this can cause the soil to retain too much water.
For plant diseases like powdery mildew, botrytis, black spot, and other fungi, you can try an insecticidal soap formulated for this use. One home remedy is to dissolve baking soda in water and spray the foliage (4 teaspoons per gallon of water, adding a few drops of dish-washing liquid). For persistent fungal problems, fungicides labeled for indoor use are available. Good light and air circulation will help control fungus inside.
If you do decide to use a chemical insecticide or fungicide, choose one formulated to treat your specific problem. Be sure to read and follow all label directions. Using the wrong chemical wastes money exposes you and the environment to unnecessary risks, and may further damage a struggling plant. On top of that, pests and diseases can develop immunity to overused products. Whenever you’re unsure, don’t be afraid to bring a cutting or sample of your plant into one of our nurseries for analysis. Our experts will be able to diagnose your problem accurately and recommend the appropriate product to help you overcome it.