How to ‘winterize’ your plants to survive the cold months

Over the course of the pandemic, the plant parenthood trend led to booming business for many plant stores, as those stuck inside their homes during lockdowns craved a connection with nature.

However, as temperatures begin to drop, all those tropical plants that were thriving in the summer aren’t going to love the coming Canadian winter.

If you had plants outdoors, Breakfast Television‘s Frank Ferragine says those must be brought in before temperatures drop down to the freezing mark.

“If by chance you’ve already had some plants that got touched by frost, you can try to remove some of those leaves,” said Ferragine. “However if they’re severely infected by frost and those leaves have all turned black, that plant has gone.”

For the plants that manage to avoid that frosty fate, popular plant consultant Julia Rago, better known as Toronto Plant Girl, says there are several steps you can take to give them the best chance to survive and thrive through the winter.

“Tropical plants — the winter in Toronto is definitely not their ideal environment,” she explains. “In our homes, we put our furnace on, but the plants are going to feel any cold windows or cold drafts, they’re going to feel the really dry air. So there are things you need to do to get them ready.”

How to winterize your plants

Step 1: Check for pests 

When you first bring a plant indoors from your garden or balcony, Rago suggests spraying it thoroughly with water or even taking it into the shower to wash off any unwanted hitchhikers, including bugs dust and dirt.

Pests also lay eggs in the soil, so removing old soil and re-potting the plant will help get rid of them. [See step 2]

Rago says skipping this step is one of the biggest mistakes you can make when you bring your plants inside for the winter.

Step 2: Re-pot the plant

When re-potting a plant, it’s best to increase the size of the pot in small increments. Rago says a pot about two inches larger than the previous one will suffice.

This is also a good time to check on root health — mushy, brown roots signal rotting and an unhealthy plant. Creamy, stiff, white roots indicate a healthy plant.

Watch a repotting demonstration:

• First loosen the plant so it is easier to lift out by massaging or rolling the pot on all sides. Once it feels loose inside the pot, lift it out gently
• If the plant is rootbound and the roots are tightly stuck together, separate the strands gently to avoid breakage.
  “You want to take your time with this, there’s no need to rush. It’s probably the scariest part for a lot of people, but once you start it’s not as bad as you think,” assures Rago.

• Prune off any dead leaves and stems.
  “Leaving a lot of decaying plant material around plants invites pests,” explains Rago. “[Dead material] shows that the plant is weaker and it’s easier for pests to come in and feed off that.”
• Add a small amount of a chunky soil mix to the bottom of the new pot — a mix with pearlite and bark is recommended. Carefully place the plant into the new pot, ensuring all the roots fit inside.
• Add new soil up to the soil line to fill the pot.

Step 3: Add natural fertilizer and diatomaceous earth

Rago recommends using natural fertilizers like worm castings instead of synthetic fertilizers, especially during the winter when most plants are not actively growing. They do not cause root burn like some synthetic fertilizers when used improperly and enrich the soil organically.

She also says diatomaceous earth powder is a good add-on.

“It is a natural pest killer. Sprinkling a little bit on top of the soil will help kill any bugs and any egg sacs that are in the soil,” says Rago.

Step 4: Spray with insecticide

Spraying with an insecticide is recommended whether or not you see pests on your plants, and Rago says it acts as a preventative as well.

“A lot of bugs will accumulate under the leaves and the crevices of the stems, so that’s where you want to focus,” she explains.

Once you finish spraying, wipe down all the leaves while wearing cotton gloves or with a microfibre cloth.

Step 5: Water thoroughly

After you’ve cleaned, re-potted and sprayed your plant, give it a thorough watering to help it settle into its new pot. Water until you see the water seep out of the drainage holes.

“[This] means the water has hit the roots, which is what we want. Now it is ready for its new home [indoors],” says Rago.

Creating conducive indoor conditions

With the heat on throughout the winter, the air in your home is going to get quite dry. Rago suggests bumping up humidity levels in your home to counter this effect, noting most tropical plants do well with higher humidity.

“Otherwise you will get lots of browning on the leaves,” says Rago.

In addition, you may have to compensate for the lack of sunlight and fewer sunny hours in the day. Rago says you should try to move your plants closer to the window and invest in inexpensive grow lights.

“Keeping a grow light on for a couple of hours throughout the day will help supplement that lost sunlight that we don’t get during the winter,” she says.

Avoid this critical mistake

Rago says most people have a watering schedule for their plants, but it needs to change in the winter.

“Your plants are going to dry out so much faster in the summer because there’s so much more and there’s tons of heat and it’s using all that energy in the soil to create lush, new growth,” explains Rago. “In the winter it’s not doing that as much so you want to draw back on that watering.”

Instead of sticking to a schedule, Rago says it’s best to let the soil dry out a fair bit before watering. She suggests checking the soil moisture levels with your finger, a chopstick or a water metre before giving your plant its next drink.

When it comes to watering, Ferragine echoes Rago’s concerns.

“The number one killer of indoor plants is overwatering,” he says.