Bring houseplants inside before nights drop below 10°C (50°F). Wash each plant, check the pot for hitchhikers, and keep it away from your other plants for two to three weeks.
A summer outdoors does houseplants good. They also pick up aphids, spider mites, slugs, earwigs, and ants. One plant can carry pests to every pot in the house. An hour of work at the door saves a winter of spraying.
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When to bring plants inside
Go by the night temperature, not the calendar.
| Plant | Bring it in when nights reach |
|---|---|
| Tropical foliage: monstera, pothos, philodendron, calathea, palms, figs | 10 to 13°C (50 to 55°F) |
| Tropical bloomers: hibiscus, gardenia, jasmine | 10°C (50°F) |
| Succulents and cacti: aloe, jade, snake plant, echeveria | 7 to 10°C (45 to 50°F) |
| Christmas cactus | 5 to 7°C (40 to 45°F). Cool fall nights help it set buds. |
Do not wait for a frost warning. A single frost can kill a tropical plant, and cold damage starts well above freezing.
Earlier is easier on the plant. When you move it in while the windows are still open, the air inside and outside is about the same. Move it in after the furnace is on, and the plant goes from cool, damp air to warm, dry air in one step.
Step 1: get the plant used to less light
Even bright shade outdoors is far brighter than a sunny room. A plant moved straight in has more leaves than the indoor light can feed, so it drops some.
Two weeks before the move, shift the plant to a shadier spot outside. A covered porch or the north side of the house works. The plant starts to adjust while the weather is still mild.
Step 2: check every part of the plant
Do this outside, in good light.
- Leaf tops and undersides. Look for clusters of small green, black, or white bugs, fine webbing, sticky spots, and pale speckles.
- Leaf joints. White cottony fluff means mealybugs.
- Stems. Small brown bumps that scrape off with a fingernail are scale.
- The soil surface. Look for slugs, snails, and ant trails.
- Under the pot and inside the drainage holes. Slugs, earwigs, pill bugs, and spiders hide there.
Tap a branch over a sheet of white paper. Specks that move are mites or thrips.
Step 3: clean it up
Trim before you wash. There will be less plant to clean.
- Cut off dead, yellow, and damaged leaves.
- Cut back long, weak stems. Vines that grew a lot over summer can lose a third of their length.
- Pick dead leaves and debris off the soil.
Step 4: wash the leaves
Lay the plant on its side, or tilt it, and hose it down. Use a firm spray, not a hard jet. Hit the undersides of the leaves, where most pests sit. Rinse the stems and the outside of the pot.
For a plant too big to tip, spray up from below with the hose.
Water alone knocks off most aphids and spider mites.
Step 5: clear out the soil
Some pests live in the pot, not on the leaves.
Soak the pot. Fill a bucket or tub with lukewarm water. Lower the pot in until water covers the soil. Hold it there for 15 to 20 minutes. Ants, earwigs, pill bugs, and slugs float up or crawl out. Lift the pot and let it drain well.
Skip the soak for succulents, cacti, snake plants, and ZZ plants. They rot when the soil stays wet in cool weather. For those, slide the plant out of the pot, look over the root ball, and brush off what you find.
Or replace the top layer. Scrape off the top 2 to 3 cm (1 in) of soil and add fresh mix. That removes eggs and debris near the surface.
Scrub the outside and the bottom of the pot with soapy water. Wash the saucer too.
Step 6: treat if you found pests
If the check turned up bugs, treat the plant outside before it comes in.
Insecticidal soap works on aphids, spider mites, mealybugs, and young scale. Buy a ready-to-use spray made for houseplants. Amazon carries insecticidal soap sprays. Follow the label directions. Spray until the leaves drip, and cover the undersides. Do it out of direct sun.
Soap only kills what it touches, so one spray is not enough. Repeat on the schedule on the label.
Wipe scale and mealybugs off by hand with a cotton swab dipped in rubbing alcohol.
If a plant is covered in pests and cheap to replace, take a few clean cuttings and compost the rest.
Step 7: quarantine for two to three weeks
Put the summer plants in a room away from the plants that stayed inside. A spare room, a bright laundry room, or one end of the house works.
Check them twice a week. Eggs that survived the wash will hatch in this window. If pests show up, treat again and restart the clock.
Wash your hands and tools after you handle the quarantined plants.
Step 8: settle the plant in
- Give it the brightest window you have. The drop in light is the hardest part of the move.
- Water less. A plant in lower light uses less water. Check the soil with a finger first.
- Stop feeding until spring.
- Keep it away from heat vents.
- Do not repot now unless the plant is bursting out of its pot. Wait for spring.
Why leaves drop after the move
Expect some yellow leaves in the first month. The plant is shedding leaves it cannot support in lower light. New leaves that grow indoors are built for indoor light, and they stay.
My fruiting figs drop leaves every time I move them outside and back in. Weeping figs, hibiscus, and jasmine are known for it too. Keep the care steady and wait.
Worry only if leaves keep dropping after six weeks, or if stems go soft. Check for wet soil and for pests.
In my house
My snake plants and my monstera go outside for the summer. I carry them back in before the nights turn cold.
The monstera is heavy. Sometimes it misses the shade, and the leaves burn and shrivel in direct sun.
The move out in spring needs the same care. My aloe goes out on the north side of the house first, or it scalds to a pale gray. Gentle changes in light work in both directions.
What goes wrong, and the fix
| What you see | Cause | Fix |
|---|---|---|
| Tiny flies a few weeks after the move | Fungus gnats in wet soil | Read how to get rid of fungus gnats |
| Fine webs and speckled leaves | Spider mites that hatched indoors | Rinse the leaves, treat with insecticidal soap, and raise the humidity |
| Sticky leaves | Aphids, scale, or mealybugs | Find them, wipe them off, and treat |
| Yellow leaves in the first month | Lower light | Normal. Give the plant your brightest window. |
| Yellow leaves with wet soil | Too much water | Let the soil dry. Water by touch. |
For the months that follow, read winter houseplant care in a cold climate.
Quick answers
When do I bring houseplants inside? Before night temperatures drop below 10°C (50°F).
How do I get bugs out of the soil? Soak the pot in a bucket of lukewarm water for 15 to 20 minutes, or replace the top layer of soil.
Do I need to spray every plant? No. Wash every plant. Spray only the ones where you find pests.
How long do I quarantine a plant? Two to three weeks, in a room away from your other plants.
Is it too late if there was already a frost? A light frost may only damage the outer leaves. Bring the plant in, cut off the black parts, and wait for new growth.