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The Avid Gardener: Preparing to Bring Plants Indoors

by and on September 22, 2017 4:30 AM

“As Gregor Samsa awoke one morning from uneasy dreams he found himself transformed in his bed into a gigantic insect.” — Franz Kafka, “The Metamorphosis”

Sometimes, just the thought of garden pests becomes a nightmare for any gardener. Yesterday, I spotted black and yellow clusters of sawfly larvae on the undersides of my yellow twig dogwood. I couldn’t dash for the jar of soapy water fast enough. Luckily, it is later in the season, so they won’t do any lasting damage, especially if they are picked off and find a watery end.

None of us want pests to hitchhike on plants we bring back indoors for the winter. Some plants make good candidates for wintering over and some should hit the compost heap. Here are considerations I weigh with my limited inside space:

■ Where can the plants be placed where they will get the best available light and be away from drafts and heating vents?

■ How truly healthy is the plant?

Any plant that is already looking sickly will likely not improve with less humidity and greatly decreased light indoors. Note that a southern exposure or grow light provides the best light.

■ How big is it?

Large plants, such as mature Boston ferns, take up quite a bit of space and a large pot can be difficult to move. It may make more sense to gift the plant to another gardener or to take cuttings for next season.

■ Can the plant(s) be used in something decorative over the fall and winter seasons?

For instance, any succulents I now have on the back porch will be taken indoors to be used to decorate pumpkins.

■ Can I eat it?

Herbs fall into this category.

■ Is it unique in some way?

I recently read of taking gerbera daisies indoors for the winter for a colorful accent. It could be worth a try.

I consider bringing plants indoors when nighttime temperatures are consistently dipping below 45 degrees in the evenings and before a chance of frost, which means this month in Centre County.

Once I have narrowed the candidates to a manageable number, there are ways to ensure that the plants come inside with the best chance for survival. Douglas Spilker’s article in “Pennsylvania Gardener,” found at offers good suggestions:

 Inspecting the plants

Remove any yellowing leaves and prune back spindly growth. Remove dead and rotting material from the soil surface so that it does not harbor pests that like moisture, such as slugs and snails or insect eggs.

Inspect all parts of the plant for such pests as mealybugs, scale, mites, aphids and caterpillars. Other insects, such as spiders, wasps or ants, also could be present. Pick off those that are larger and hose off the plant well.

 If they are infected

Spilker suggested that the plant be treated outside with a low-impact pesticide such a horticultural oil, insecticidal soap or pyrethrum if there is extensive evidence of sticky leaves, mite webbing or stippling (yellow dots).

 Treating the pots

The outside of pots can be scrubbed with a solution of 10 percent bleach to remove dirt, mold, mildew and mosses. Smaller pots can be submerged in a tub of lukewarm water for about 15 minutes to see what comes to the surface. 

It is always possible to repot the plant, but first spray the root mass with the spray of a hose and scrub the inside of the pot with the bleach solution. Be sure to rinse it well before repotting the plant.


I believe it is wise to try to keep the plants being brought indoors in a quarantine from other house plants for two to three weeks.

With most plants, like my Meyer lemon tree, I’ll gradually accustom them to less light and warmer indoor temperatures by moving them inside at night and out during the day until the cooler daytime temperatures prevail. This alleviates plant shock, leaf loss and dieback, though some decline (like leaf loss) is normal. If pests emerge during this transition time, treat the plant in a place like the garage.

Two pests that are common problems with indoor plants are fungus gnats and spider mites. Fungus gnats like moist soil, so letting the plants dry out between watering can help alleviate them. Spider mites like hot, dry environments, so it may help to increase the humidity around the plants. However, it is usually recommended to discard a plant with spider mites since they can easily spread to others.

Only water a plant when the soil is dry. If in doubt, skip the watering (I often will if it is cloudy or rainy outside). However, when watering, water thoroughly to wet the entire root ball and help leach away excess fertilizer salts built up in the soil.

I generally do not fertilize over the winter months. If I do, it’s done sparingly, diluted by 50 percent or more.

The German author of “The Metamorphosis,” Franz Kafka, never wanted the type of insect Gregor Samsa had become to be drawn, leaving its identity purposely mysterious for readers. Luckily, modern gardeners, thanks to science, no longer have to rely too much on their imaginations.


This story was produced by the staff at the Centre County Gazette. It was re-published with permission. The Centre County Gazette is a weekly publication, available at many locations around Centre County every Thursday morning.

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