Already Time to Bring Your Houseplants Back Indoors?

Houseplants love spending a summer in the great outdoors … but at some point, you have to bring them back in. Photo: www.stamenandstemblog.com

With the days getting shorter and the nights getting a tad chillier, you can tell that fall is on its way. And before it arrives, it’s time to bring in the houseplants that have spent their summer outside. Philodendrons, palm trees, hibiscus, etc.: if you carried them out of the living room at the start of summer and placed them outdoors on your patio or balcony or even integrated them into your flower beds, now is the time to seriously consider bringing them indoors again. The same goes for the herbs that can successfully be overwintered indoors, like bay leaf and rosemary. And many annuals are salvageable too: begonias, coleus, pelargoniums (geraniums), fuchsias, etc.

If you want to save these plants, now is the time to think about it.

When to Bring Houseplants In? 

Obviously, the local climate will be an important factor in deciding when to bring plants back indoors. Where temperatures drop early, as in Canada and Scandinavia, you should probably bring them in before mid-September, but in other regions, such as southern Europe and the southern United States, there may be no cold before November. And of course, if your climate is tropical, you won’t have to bring in your plants at all.

To know when bring them in, just check out your local weather forecast. As soon as nighttime temperatures start to drop even a smidgen below 60 °F (10 ° C), it’s time to act.

Why only 60 °F (10 ° C)? I mean, that’s well above freezing! True enough, but remember, it’s not just frost that tropical plants fear. They don’t like cold at all … and most houseplants are indeed tropical. Even when nights are just a bit cool, these plants already start to react: leaves turn yellow and flowers drop off. Some may even go into a state of shock from which they never recover.

However, if you bring them in before the temperatures drop below 60 °F (10 ° C), often the transition goes ahead without the slightest negative reaction.

Bring in Your Plants, Not Their Pests

So far, so good, but how do you bring plants indoors without the unwanted insects and other pests hitching a ride? Fortunately, it’s not that hard to do. Here’s how:

First, give them a thorough cleanup. Remove dead and yellow leaves, trim branches that are too long, etc. Then, hose down the entire plant with a strong spray of water. That will actually be enough to kill or wash off many insects, but … why take chances? So, after this, spray the plant with insecticidal soap (available at any garden center). Do not use dishwashing liquid: it often contains products that are toxic to plants.

Make sure the soap solution reaches on all exposed parts of the plant and especially the undersides of the leaves and leaf axils, two places where insects tend to hide.

So much for treating the leaves, stems and flowers. What to do with insects and other critters that may hide in the soil?

You can remove soil pests simply by immersing the pot in a large bucket of water to which you add a bit of insecticidal soap (about 1 teaspoon per quart/liter), then leave the root ball to soak for 10 to 30 minutes. You may need to put a brick or rock on top of the root ball to keep it immersed. Then remove the pot from the bucket, let it drain well, then wipe the pot clean before bringing the plant in. Soapy water will kill just about any little creature that might have been hiding in the soil.

Or Take Cuttings

Of course, it’s possible to dig up annuals like begonias, coleus, fuchsias and pelargoniums from the garden and pot them up, and then give them the treatment shown above, but it’s often easier just to take cuttings. Plus, this way, you bring in a smaller plant that will take up less space.

Taking stem cuttings from appropriate annuals (here is a list of annuals you can grow from cuttings) is simple enough. Start by clipping off a terminal section of stem about 4 to 8 inches (10–20 cm) in length, depending on the size of the plant. Remove the lower leaves and any flower buds or flowers. Now immerse the cutting in soapy water and swish lightly to eliminate any pests that may be hiding there. Let the excess moisture drip off.

Prepare a small pot of moist potting soil and insert the cutting into it up to the second node (bulge on the stem where a leaf was once attached). For woody (hard stemmed) cuttings, such as hibiscus and fuchsia, apply a rooting hormone to the lower end of the stem before you insert it into the soil to stimulate faster rooting. Cover the cutting with a “mini-greenhouse”: a clear dome or clear plastic bag. It will maintain high humidity and thus reduce stress to the cutting, inducing faster rooting. Now place the cutting in a well-lit location, but not direct sunlight.

Cuttings from succulent plants (cacti, euphorbias, sedums, etc.) don’t need a mini-greenhouse (unlike most plants, they don’t like high atmospheric humidity). They’ll root better in open air.

When new leaves appear, normally within a month or so, the cutting is rooted and will now be able to live on its own. Just remove the bag or dome and place the young plant in a location that best suits its needs.

Winter Care

During winter, water your plants when the soil feels dry to the touch and maintain good atmospheric humidity for any with thin leaves. Place in as brightly lit a spot as possible, as fall and winter sun is usually weak. If the location is dark, use a grow light to complement or replace the sun. After you bring your plants indoors, hold off on fertilizer: they won’t be needing it until the days lengthen again in March.

Bringing plants back indoors: not as difficult as it seems!