As summer nears its end, you should begin to think about reintroducing your houseplants to the indoors. There are a few things you will want to do before bringing plants inside.
Check your plants’ leaves. Insects can hide on the undersides and in between closely clustered leaves. Dish soap in tepid water can be used to remove pests, either by gently wiping down leaves with a washcloth or by tipping the plant upside down and swishing it carefully around. If you are going to invert the plant and dunk it, cover the top of the pot with plastic wrap to prevent the potting mix from spilling out. This treatment may need to be repeated weekly for several weeks to get rid of all leaf-dwelling pests.
The pot should be considered, as well. Insects may have made a home inside of it during the warm weather, or may have ventured inside more recently looking for a place to spend the winter. Tip the plant out of the pot to have a look and shake loose any unwanted residents. Now is also a great time to check the health of the roots of your plant; they should be firm and white. If they are brown, mushy, or if you don’t see many (or any), you may have root rot.
You can flood the pot with water to be sure you’ve gotten all of the insects out. Plug the bottom hole and water the plant until water covers the surface of the potting mix. Leave it to sit for about half an hour to an hour. Insects will either come to the surface or drown. You can use an insecticide in your drench if you want to kill any grubs or early hibernators that may be hiding.
Now is also a great time to place a systemic insecticide in the pot as a barrier against future predation. A granular product such as Marathon is easy and effective.
When you bring the plants inside, keep them separate from clean plants that have stayed indoors over the summer until you know that all insects have been eliminated. It wouldn’t be very fun to have to treat your indoor plants after you thought you’d gotten rid of everything.
Expect to see some leaf loss after bringing plants indoors; the change in humidity and light levels causes stress which results in defoliation. Try to place plants in an area with light levels similar to what they were receiving outside. This will probably be one of the brighter areas in your home. Grouping plants together will help decrease water loss. Misting and use of humidity trays is also helpful.