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Bring houseplants back indoors before nights fall below the minimum temperature suitable for each species. A calendar date or the absence of frost is not enough: tropical foliage plants can suffer in chilly weather well above freezing. Check the forecast, prepare a bright indoor position and inspect each plant before it joins the rest of your collection.
Table of Contents
Use the plant’s minimum temperature
A plant label or reliable species guide is more useful than one rule for every houseplant. Some plants tolerate cooler autumn nights; others need consistently warm conditions and may be best kept indoors throughout a UK summer. Move the sensitive ones first, and do not wait for a cold snap to test their limits.
If the weather is still suitable, ease the change by moving plants to a sheltered, shaded outdoor position before their return indoors. If cold is imminent, bring them in promptly rather than extending an acclimatisation routine.
Prepare the indoor position
Choose light and temperature to suit the plant. Indoor light is usually lower than outdoors, even close to a window. Keep leaves away from cold glass and avoid both radiator heat and cold draughts. A frost-free garage appropriate for dormant tender garden plants is not automatically a suitable winter home for a tropical houseplant.
Clean the saucer or decorative outer pot and protect furniture from drainage. Check that the plant can drain freely and will not sit in collected water.
Inspect before mixing with other plants
- Check foliage: look under leaves, along stems and in leaf joints for aphids, scale, mealybugs, whitefly or fine mite webbing.
- Check the container: inspect rims, drainage holes and the underside for slugs, snails and other sheltering animals.
- Tidy gently: remove dead leaves and debris. Clean suitable smooth leaves with a damp cloth; avoid unnecessary pruning or disturbing sound roots.
- Keep apart initially: place returning plants separately from the main collection while you inspect them repeatedly over the following weeks.
If pests are found, identify them before choosing treatment. Use a method appropriate to the plant and, for a purchased product, its current label and indoor-use instructions. Do not apply garden pesticides or nematodes simply because it is September.
Do the roots need inspection?
There is no need to unpot every healthy plant as part of its return indoors. Investigate the rootball if growth, instability, pests or poor drainage give a reason. If repotting is necessary, choose a medium suited to the species and avoid a much larger pot full of wet compost. Otherwise, wait for the plant’s normal repotting season.
Reset watering and feeding
Check the compost rather than continuing the outdoor watering schedule. Lower light and slower growth often mean less frequent watering, while a warm bright room may keep some plants active. Let surplus water drain, and check inside cachepots after every watering.
Reduce or pause feeding when growth slows, following species and fertiliser guidance. More feed will not compensate for insufficient light.
Watch the adjustment
Some leaf drop can follow a change in conditions. Brown tips or yellowing are not a diagnosis of low humidity: check root moisture, drainage, light, cold and pests as well. Keep humidity-loving species away from hot radiators, and use their specific care guidance rather than treating every leaf problem with extra water or misting.
Recheck plants weekly while they settle, with gentle air circulation and no cold draught. If decline continues, inspect the likely cause before repeatedly moving, watering or repotting the plant.
Useful products for this job
The links below open Amazon UK product searches. Check the exact item, seller, current price and compatibility before buying.
- Indoor minimum–maximum thermometer: Helps check whether a proposed indoor position remains warm enough overnight. Check readable minimum/maximum memory and the temperature range; place away from direct sun and radiators for a useful room reading. Search Amazon for Indoor minimum–maximum thermometer.
Related garden guides
- Overwintering plants in an unheated greenhouse
- How to refresh old container compost
- More greenhouse & growing guides
Sources and further guidance
- RHS: Moving houseplants outdoors for summer
- Overwintering plants in conservatories | RHS Advice
- Monthly gardening tips & advice – September – tender plants / RHS
- Monthly gardening tips & advice – July – tender plants / RHS
Guidance researched in September 2026. The feature image is an AI-generated illustration. Product guidance is based on published information, not hands-on testing.