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Nov. 29, 2021 | Monday
Editorials and Opinions
Growing Together: Frost is coming, time to bring house plants in for winter
If you're bringing plants like this croton indoors for the winter, several preparation steps are necessary. (Joanne Young photo)

It is hard to believe that we are now in the first week of October. September was such a warm month, that it just doesn’t seem possible.

But the daytime and nighttime temperatures are cooling down and fall is here. If you haven’t yet done so, now is the time to be bringing in those indoor plants before the temperatures get much lower.

A good rule of thumb for when to bring them in for the winter is at least two to three weeks before your average first frost date. In Niagara, the average first frost hits between Oct. 21 and Nov. 10.

Although most houseplants can tolerate temperatures between 5 and 10 Celsius, if they are left outside for too long, a cold night could trigger them to drop their leaves or possibly kill the plant.

Also, if you leave them out too long, the plants will go through more of a shock due to the greater change in temperatures and light conditions. So, the sooner you can bring them in, the better.

It is important to take a few steps to successfully make this transition a smooth one.

Before you bring your plants inside you will want to:

Inspect them for any insect infestations such as aphids, mealybugs and spider mites. This is crucial to keeping your plants healthy.

A few simple steps can ensure your houseplants are bug-free before bringing them back indoors in the fall. First, fill a large tub or bucket with water and add a few squirts of a mild liquid soap.

Do not use any soaps that contain degreasers or detergents. Those can damage (or even kill) sensitive plants. Submerse that entire root ball into the water/soap solution and let sit in there for about 15 minutes. This will help to get rid of any insects in the soil.

Next, inspect the leaves closely, looking for any signs of insects, eggs or damage such as fine webbing, or yellow or brown markings on the leaves. Make sure you examine the underside of the leaves as well. You may want to spray your plants with insecticidal soap to kill any insects. Giving the pot a good scrub is also a good idea.

Remove any diseased leaves and discard them.

Check to see if your houseplant is pot-bound. There are a couple ways to tell if your plant needs to be repotted.

If it is a smaller-sized plant, you can tap on the rim of the pot and allow the pot to slide off. A pot-bound plant will have many roots tightly wrapping around the outside of the root ball in a circular pattern.

Another way to know if your plant is pot-bound is that the soil will be pulled away from the edges of the pot and when you hydrate it the water just runs straight through the pot. Move it into a new pot the next size up, making sure that there is adequate drainage. Use an all-purpose potting soil or soilless potting mix.

Trim back plants, if needed. If your houseplant has flourished outside, it may need to be trimmed back before bringing it inside. You can safely prune back up to one-third of its growth.

Now you are ready to bring your plants inside.

To start off, keep them in the sunniest window in your home before gradually moving them to their usual indoor spot over the next few weeks to help them acclimate to the lower light conditions indoors.

You can expect your plants to lose some of their leaves once they come indoors because even the sunniest window in your house still offers lower light conditions than what they had outside.

Your plants will not need as much water as they did when outside so make sure you monitor the soil moisture. Let the soil dry out on the surface before watering. Keep an eye out for signs of insects or diseases problems, and deal with them as soon as you see them – before they become a major problem.

Now your indoor plants are all tucked in and ready for winter.

Joanne Young is a Niagara-on-the-Lake garden expert and coach. See her website at