When to bring plants inside

Bring tropical houseplants inside when nighttime lows are forecast to drop below about 50–55°F — weeks before the first frost. Hardy succulents can wait until the low 40s. Don’t use frost (32°F) as your signal: by then, many tropicals have already been damaged.

Check the 10-day forecast for your ZIP code on the National Weather Service site, and plan the move for a dry day.

Temperature chart by plant type

In most of the northern US, nights hit the low 50s in September; in the South and along the West Coast, often not until October or November. Your USDA hardiness zone tells you how cold your winters get, but the forecast tells you when to move the pots.

5-step checklist so you don’t bring bugs in

1. Inspect leaf undersides, stems and the soil surface for spider mites, aphids, mealybugs and scale.
2. Rinse the whole plant with a hose (gentle spray), including leaf undersides.
3. Check the pot — slugs, ants and earwigs hide under pots and in drainage holes. Soak the pot in a bucket of water for 15 minutes to flush out soil critters.
4. Quarantine in a separate room for two weeks before it joins your other houseplants.
5. Trim leggy or damaged growth now, so the plant doesn’t spend winter feeding it.

Help it adjust to indoor life

Outside, even shade is brighter than most rooms. Expect some yellowing and leaf drop in the first 2–3 weeks. To soften the shock:

• Bring it in gradually if you have time: a few days on a covered porch first.
• Give it your brightest spot — near a south- or west-facing window. Not sure how bright a spot is? Try the hand-shadow light test.
• Water less. Indoors in winter, plants use far less water than outside in summer. Check the soil first; the watering chart has typical winter ranges.
• Keep it away from heater vents and cold, drafty doors.
• Skip fertilizer until spring.

Plants that can stay out

Hardy perennials, shrubs and trees in the ground are rated for your zone and stay put. Containers are a different story: roots in a pot are much more exposed to cold than roots in the ground. In zones 6 and colder, move potted perennials against the house or into an unheated garage once they go dormant.