With the weather cooling off, it is time to start considering which plants to bring in for the winter and what steps need to be taken to prepare them for the shift in location.
It would be wonderful if we all just needed to drag those outdoor plants into the house and let them sit for a few months. The reality is that not planning could be disastrous for both our houseplants and their seasonal company.
Elements like sunlight, humidity, and temperature are all things that will change for these outdoor plants when you bring them indoors. Pests and diseases brought from outside also threaten those who live indoors year-round.
All of these factors, plus a few others, and how well we prepare for them, affect how well our outdoor and indoor plants survive the winter. Let’s discuss 11 things you can do to prepare those outdoor plants to come inside during the colder months, and hopefully, we will enter spring with as many as we started with.
Determine Which Plants Should Come Indoors
Some plants are easily identifiable as tropical and need protection in cold weather.
Before you start digging things up and hauling pots indoors, it’s a great idea to determine which plants need to come indoors and which will be perfectly fine where they are. This can be a simple task if you know the names of all your plants, but I’ll be the first to admit it can be challenging to keep track of all the names.
Some we can make assumptions about. Anything tropical needs protection in cold weather, and tropical plants often have a particular, distinctive look about them. For example, orchids, gingers, begonias, alocasias, and colocasias must be brought indoors in most winter climates.
Your Climate Zone
The best way to determine this is to find out what climate zone each of your plants is suited for and go from there. This can get a little tricky around zones seven through nine. I’m in zone eight, and many fall directly to one side or the other around here. So, it can be a roll of the dice.
In my zone, I practice survival of the fittest regarding the plants in the ground. Most things survive, many others come back, and the ones that don’t, well, I figure they just weren’t meant for me. However, you may have something you love in the ground, so we will talk about moving those indoors, too.
It truly doesn’t pay to plant large things that won’t survive in your climate zone, but for others, such as rhizomatic ginger or tuberous dahlias, it is not difficult to make room for them indoors, as you will just be digging up their roots, and storing them in a cool dark place for the winter.
Pay Attention to the Weather
Cold weather serves as a signal, indicating it’s time for the plant to go dormant.
Once you know which plants need to come indoors for the winter and what temperatures they can tolerate, you can make a plan and monitor the weather. Some tropical types must come inside when the temperature drops below 50°F, while others are surprisingly cold-tolerant.
Knowing what temperature your plants can withstand is important. It is also good to know whether or not they go dormant for the winter months. Many plants die back to the ground and enter dormancy. They need some cold weather to let them know it is time to go to sleep.
Some orchids, such as deciduous dendrobiums and cymbidium orchids, need a slight drop in temperature for a few weeks to set buds. The shortening days and cooler weather are their queue to redirect energy away from foliage and into flower development.
Keep an eye on the weather forecast, and try not to cut things too close. We’ve all known the heartbreak of an untimely cold front. At least, those living outside the tropics do. It’s all college football and sweater weather until your begonias drop leaves. The story’s moral is to bring your plants in before it gets too late.
Tidy Up and Inspect for Damage
Indoor damage can result from bringing a single plant with a fungal issue or a group of spider mites.
I don’t know about you, but most of my houseplants look tidier than the ones I grow outside. Sure, I might clean things up if I expect company in the garden, but there are typically more brown leaves on those outdoor plants than I want to look at in my house all winter.
This is a great time to inspect your plants and give them a little TLC. Start by removing dead or damaged foliage, as this can be a sign of pests and diseases you don’t want to introduce to your indoor environment. One plant with a fungal issue or a family of spider mites can cause a surprising amount of harm when brought indoors, away from air circulation and natural predators.
Treat for Pests
Pesticides not only eliminate harmful insects but also harm their natural predators and pollinators.
You can do this prophylactically or on a case-by-case basis, depending on how you feel about insecticides. Some, like insecticidal soap, BT, or neem oil, are effective against many types of pests and are relatively low-impact.
You can do many things throughout the year to manage pests in the garden, and a combination of methods can make a big difference in plant health. It is important to remember that pesticides kill more than just bad insects. They also kill the predators of those bad insects and pollinators, but typically, these beneficial predators and pollinators are not indoors with your plants.
Using natural methods of pest control throughout the year will help keep your garden functioning as part of the ecosystem while they’re outdoors. Sometimes, pests and diseases can’t be avoided, and treating them before bringing them into the home is important.
Quarantine is an essential precaution when bringing outdoor plants indoors.
Another helpful step in introducing your outside plants into your indoor environment is quarantine. I am guilty of skipping this step, and it doesn’t pay. If you can identify an issue with the plant’s health, this is a must. Quarantine while you treat them to avoid the spread.
Even for plants that appear to be perfectly healthy, a one to two-week quarantine is a great safeguard. Fungal diseases can sporulate rapidly and spread if they’re not contained, and some insects are very tiny. Where natural predators may be doing a great job of keeping the mealybug population down on your Dieffenbachia on the patio, if there are unhatched eggs on the plant, they won’t show up right away. I’m speaking from experience here.
Repot or Freshen Soil
Indoor plants require more water and nutrients when in their active growth phase.
This is a great time to do any repotting or refreshing soil. Plants that have been outdoors can have fungus or pests/eggs lurking in their soil. If you have had a rainy growing season, this is especially true.
Some plants may have outgrown their space over the summer and would benefit from a larger container. Before you bring them in for the winter is the perfect time to do your repotting.
Make sure that your plants are living in the right media as well. Drainage is typically more of an issue in the winter and indoors. Most use much more water and nutrients during their growing season. Water evaporates faster outside as well. The same soil and container that works great outside in the summer could lead down a short path to root rot indoors in the winter.
Fresh soil is looser and drains well. This also replenishes the nutrients in the soil, which will come in handy in the spring when your plants re-enter their growth phases.
Rinse and Wipe Down Foliage
Before bringing your plants inside for the winter, clean them thoroughly.
Consider thoroughly cleaning your plants before you bring them inside for the winter. Flushing the soil if you haven’t changed it out can help rinse out the build-up of salts and fertilizers and give your plants a nice long drink.
Leaves can get splashed with dirt or accumulate mildew on the leaves while living outdoors. If you had any issues with insects during the year, there is a significant chance that you’ve got some sooty mold growing in the wake of their sweet, sticky honeydew (that’s their excrement, yuck!).
All of these undesirable substances can be wiped off by hand. You can carry this out at the same time that you treat pests if you are doing so. Wiping down your leaves with a soft cloth dipped in soapy water can solve several issues. Just rinse them with clean water immediately afterward to avoid damaging the leaves or removing too much of their protective coating.
Light is significant in helping your plants adjust when bringing them inside.
If you’ve never hopped from a hot tub into a cold pool, I strongly do not recommend it unless you’re into that sort of thing. I’m sure there are some health benefits to the human body from experiencing temperature extremes, but for plants, the result can be a bad case of shock.
Although temperature is unlikely to be the main issue in this case, as the outdoor temperature will be closer to that of the indoors, light is a huge factor in acclimating your plants to come indoors.
The most important types to consider in this process are the ones that prefer a significant amount of sunlight. Shade or partial shade plants usually do just fine being moved indoors, and you might find some that thrive during this time.
Plants like hibiscuses and petunias, which perform best in full sun, will likely need a more gradual transition into the home environment. Many of these will enter some degree of dormancy in the winter, and you can help them along this path by gradually adjusting them to lower light conditions.
Plants are very in tune with changing amounts of sunlight. As the days get shorter, less sun means less production of chlorophyll. This is what causes leaves to change color in the fall. As the green fades, the red, gold, and orange tones beneath begin to reveal themselves.
How to Acclimate
Move your sun-lovers into a shaded spot about a week or two before you bring them indoors. This light reduction will help them along their path to dormancy, making them much easier to care for over the colder months. Dormant plants need less light, water, and nutrients than actively growing plants.
You can take this a step further by bringing your plants in gradually, a few hours per day, and increasing that number of hours over two weeks. This isn’t always possible if the weather decides to be unpredictable. In this case, better in than out, but acclimating your sun lovers to lower light conditions is helpful if possible.
Determine Locations by Plant Needs
Different plants have varying sun requirements due to the cooler months.
My problem in the winter is always making room for plants that are coming in from outdoors. Most of this issue concerns filling every possible sunny space in my house with houseplants that live inside all year.
If you are a houseplant collector, you may have to perform some fancy re-organizing to make room. Many plants experience a period of dormancy during these cooler months, and they won’t need the same amount of sun as in the warmer months. Most will still need a spot that gets some sun, even if only for a few hours per day.
Another very important factor to account for is humidity. Most people don’t want increased humidity in their homes, but many indoor varieties are tropical. Tropical plants typically need a lot of humidity; some require upwards of 60-70% humidity to keep their leaves looking healthy.
If you have a bright, sunny bathroom, your tropical plants will likely have the easiest time getting used to that after living outdoors. The humidity is usually higher in a bathroom. If not, consider keeping your tropicals close to each other and near a humidifier. Pebble trays are great tools for raising humidity in a small space around each plant, and they require less maintenance.
Pay Attention to Poisonous Plants
It’s crucial to identify safe plants and those that should be kept out of the reach of pets or children.
If you have small children or pets living in your home, knowing which plants are safe for them and which must be kept out of reach is important. Cats seem pretty intuitive, in my experience, about what they should and should not eat, but dogs are a different story.
Philodendrons, for example, may not kill a dog, but taking a bite of one will feel like chewing on needles, which is pretty awful. Many common plants are toxic to animals and humans and should be brought indoors with care.
This is very important with a lot of bulbs and tubers. Most poisonous plants’ bulbs or root systems hold more of the toxin than their leaves and flowers. Store bulbs in a spot where your pooch or toddler can’t get into them and take a curious taste.
Consider other dangers as well, like cacti. Some cacti look dangerous to curious little eyes, but others look soft and fuzzy. Beneath that fuzz can often be sharp, stinging spines that will hurt small hands and wet noses. Set these plants out of reach to be on the safe side.
Store Bulbs Properly
Organic materials like peat can improve winter storage for bulbs and tubers such as dahlias.
Finally, let’s talk about storing bulbs, rhizomes, and bare roots for the winter. Plants such as ginger, dahlias, cannas, colocasias, and alocasias, among others, have bulbs that can be stored for the winter if you prefer to save space and not store entire plants. Some of these plants can get quite large over the season.
For some plants, like dahlias and cannas, it is important to wait until after the first frost has killed off the foliage before storing them for the winter. Others, like ginger and turmeric, are best to dig up before the temperature drops below 50°F.
Storage can vary based on the type of plant. Most bulbs and rhizomes should be cleaned and given a week or two to cure or dry. Many can be stored by wrapping them in paper and placing them in a dry, cool place that doesn’t get colder than that 50°F mark.
Some bulbs or tubers, like dahlias, will fare the winter better if you store them in some organic material, such as peat. When storing edible roots, you can save portions of the root with eyes (where new sprouts will form) to plant the next spring and store the rest for consumption.
With some foresight and a little prep work, it is possible to keep your frost-tender outdoor plants thriving through the winter inside the house. Taking those few extra steps, such as swapping out old soil, quarantining to avoid pests in the house, and helping your plants make a more gentle transition, can make a big difference in their general happiness.