Bringing Tender Plants Indoors: Houseplants & Tropicals

Houseplants

My houseplants love their outdoor summers, but all good things must come to an end. Since most houseplants are adapted to growing in low light, I place my houseplants in shaded positions in my garden and patio when I bring them out for the summer. They thrive in the open air, natural rainfall, and regular fertilization that comes along with outdoor living. Before bringing them indoors, in order to avoid hitchhiking insect pests coming along for the ride, I believe it is a good idea to treat your plants with an environmentally friendly pesticide.

Watch the weather as we get into the month of September. Since the majority of houseplants are native to tropical areas, you will want to bring them indoors well before the temperatures reach freezing. Playing it safe, I usually bring my plants in when nighttime temperatures reach 50 degrees.

My two favorite sprays for treating houseplants before bringing them back indoors are Insecticidal Soap and Neem Oil. Both are safe and certified for organic gardening while at the same time being highly effective against spider mites, whiteflies, and aphids – the most frequent insects found on houseplants. Neem Oil leaves a sticky residue that can damage indoor surfaces so I always do the actual spraying outdoors, before bringing the plants in. I also apply systemic houseplant insecticide to the soil in the pot to provide continued protection. This is slowly absorbed into the plant and provides extended protection for up to 8 weeks. Since there are no pollinators or beneficial insects inside our homes, there are no environmental concerns with systemic insecticide use indoors.

Tropical Plants

Many of the tropical plants that we grow in Wisconsin as annuals can be overwintered indoors. If you are fortunate enough to have a large south-facing window you might be able to keep them actively growing throughout the winter.

Many can also be overwintered in a dormant state. Tropicals that grow from tubers or bulbs, such as Dahlia, Canna, Gladiola, Caladium, and Elephant Ear (Alocasia / Colocasia) are easily overwintered this way. I have even had success using this technique with tropical Banana (Musa / Ensete).

If planted in the ground:

• Dig bulb/tuber before hard frost.
• Cut the foliage off at the soil level.
• Place the bulb/tuber in a breathable paper bag. Do not use plastic as it will cause the bulb to rot.
• Include a small amount of dry peat moss or sawdust in the bag with the bulb/tuber.
• Place the bag in a cool, dry place (I use the basement).
• In spring replant the bulbs once the danger of freezing is past.

If grown in containers:

• Simply bring the entire container into a cool, dry place for winter storage.
• Cut foliage off at the soil level.
• Bring the container back outdoors once the danger of freezing is past.

Another technique for your tender plants

Our Merchandising Manager, Cheryl, has a large tropical Hibiscus that she has been bringing in and out for over 20 years. Since so much light is required to keep a Hibiscus actively growing all winter, she prefers to allow hers to go dormant. She places it on a large tarp in her basement (which has small ground-level windows) and waters it sparingly every 10-14 days. The plant will drop all or most of its leaves onto the tarp and remain dormant through the winter. In mid-May, once the danger of frost is past, she brings her plant back outdoors and begins watering and feeding it regularly. She prunes it very lightly, removing only branch tips that have died over winter.  By mid-summer, she has a gorgeous, large Hibiscus, filled with blossoms!