How to Overwinter Tropicals Indoors

By Megan Nichols and Jessie Jacobson of Tonkadale Greenhouse, Minnetonka, MN.

An open letter to tropical plants and their owners:

Thank you for being beautiful and flowery and leafy all summer long. You put on a splendid performance in both the garden and in containers in which you were planted. You made me look good as I cared for you with ease.

But I must be honest, what is a gardener to do with you as the days get shorter and the nights cooler? My favorite garden center tells me I didn’t name you and you’re not part of my family, so it’s okay to let some of you go to the compost with the frost.

They also mentioned that some of you might want to move indoors for the winter. I hear that having plants in the house provides many benefits to us humans. If you love me and want to keep more alive so we can enjoy another summer together next year, here’s what I, your fabulous tropical plant, needs.

General Tips (and Tricks)

Tropical plants like the same conditions as humans. Under 50 degrees and they’re less than happy. To avoid stressing them, bring indoors at the first sign of cool evening temps.

But, before you haul them indoors, make sure they’re safe for the pets and kiddos in your life. (Check out aspca.org for pet friendly options.)

Ready? Let’s Get Started.

1. Treat for pests

Outdoor plants often become home to ants, pillbugs, or other unwanted creepy crawlies. Spray both the soil and the entire plant (leaves, stems, etc.) with insecticidal soap a week or so before you invite them into your home.

2. Re-pot if needed

Much easier outside than in, right? Repot in a container that’s at least one (two is better) size up from the current one, use fresh potting soil, and make sure your container has a drainage hole. It’s recommended to leave houseplants in their grower pot or plant them in lightweight plastic containers called liners.

3. Wash and wipe

Leave the dirt outside. Start by wiping larger leaves with a damp cloth and if leaves are smaller, hose them down. For some, it’s nice to apply a product known as leaf shine. Makes the leaves, well, shine. Do read the label as some plants including dracaena and ferns don’t fare well with this product on their leaves. For cactus and succulents, use air duster or a small paintbrush to clean the leaves. Finally, clean off dust and grime from the exterior of the pot.

4. Style your plants

Choose fabulous containers like baskets, buckets and ceramics to drop your liners into – preserving the drainage while showcasing your specimen. Make sure to reinforce the inside of your container with a plastic saucer so they don’t leak. Hang, group, combine, mix and match and/or display at different heights.  Plant collections are the new cool. Check out Instagram for all kinds of ideas – @thejungalow, @urbanjungleblog and of course @tonkadale

5. Fertilize at half strength

Just read the package directions and cut in half. And, feed less often. A water-soluble fertilizer is fine or use a compost tea brew. Hint: add a few drops of peppermint oil to your brew to make it smell fresh, not funky. This also helps keep pets away.

6. Foliage plants are easy

Easy care plants that do best indoors are generally varieties prized for their foliage and that an handle lower light conditions indoors. General light classifications are low, medium and bright. If you’ve used fiddle-leafed figs, crotons, pothos, philodendron, sansevieria, ivy, spider plant, or just about any other variety of plant prized for its leafy greens or golds, or reds or purples, re-pot and invite them to stay indoors for awhile.

7. Succuents are also welcome indoors

For cold-climate dwellers, it may come as a surprise that succulents and cactus can actually handle a little cold.  Deserts are cold at night! These can stay outside a little longer to take full advantage of the sunlight. Be sure to bring them in before they become popsicles.

Yes, Flowering Plants are More Challenging

Some varieties, which require a lot of light, are challenging to overwinter, including tropical hibiscus, mandevillas, jasmine, bougainvillea and citrus. They require a sunny window in a room where air temperature stays about 60-70 degrees and a humidity level between 30 and 45 percent (mist leaves or place a pan of water among the plants).

In cold climates, keep the humidity below 30 percent to avoid condensation on your windows. The ideal winter environment for most flowering tropical plants would be approximately 50 degrees at night and 65 degrees during the day. Don’t be tempted to jack up the heat, as warmer air temperatures can lead to leggy growth and insect problems.

If you plan to let your plants simply go dormant, let them rest in a cool place (40 to 50 degrees F) with little or no light—their leaves will gradually yellow and drop.They can then spend the winter in an unheated basement, unheated garage, or even a cool closet. Water sparingly – about twice per month.

If you want to try and keep them as houseplant and maybe even coax a few blooms (success is generally a cross between the right conditions and sheer luck), follow these instructions:

Tropical Hibiscus:  Prune hibiscus 3 times between now and spring, first at the end of October, then again in December, and in February. Cut back each stem by about 50 percent to maintain good shape, and keep the plant from becoming leggy. Set your calendar reminders and just do it.

Mandevilla, Jasmine & Bougainvillea: They’re likely in flower now, but flowers will diminish quickly as the days shorten. Prune back by about 25% so they don’t have to work so hard to keep their long vines alive. Don’t be alarmed if they drop leaves–just continue to care for them and they will re-leaf in time.

Citrus: Not only do citrus trees and shrubs require a lot of light, they can also grow quite large, so they require a bit of room. Prepare for this in advance as once you find the right spot, you don’t want to have to relocate due to too tight a space. Given the right conditions–placed in a south-facing window with good airflow and if necessary, supplementing sun with a grow light during dark winter months–these will actually bloom in fall or early winter (intoxicatingly delicious) and set fruit in winter or early spring. It’s a fun process, but oh-so-slow, so prepare to be patient.

Final Thoughts

Know that growth and blooms on overwintered tropicals will appear later in the season then a grab-and-go container from the garden center.

Water carefully. Often our heated homes become quite dry, which can cause plants to lose moisture quickly. However, plants aren’t actively growing during the winter months so they don’t require as much water.Test the soil using the tip of your finger, if the top inch is dry go ahead and water. Practice makes perfect.

Watch for pests. Mealy bug, scale, aphids, and others all show up at the darndest times – like January (how do they do that?). Treat with insecticidal soap or neem oil. Read the directions.

Feeling bad about failure is not allowed. It’s not the end, it’s just the beginning of a trip to your favorite garden center for new indoor plants.

Plant plants (even indoors). It’s important.

About Tonkadale Greenhouse:

Tonkadale is a design driven garden center located in Minnetonka, Minnesota. Pollinator friendly. Kid friendly. Dog friendly. Always original. Always approachable. Your greenhouse home.

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