Maintenance

What temperature is best for most houseplants?

March 12, 2026 1 min read

Most tropical houseplants perform best at temperatures between 18 and 25 degrees Celsius, which corresponds to the typical range of a normally-heated UK home during the day. 

Minimum Safe Temperatures by Species Group

Most aroids (Monstera, Philodendron, Pothos, Scindapsus) and Calatheas can tolerate brief dips to around 12 to 13 degrees Celsius but prefer a minimum of 15 degrees Celsius.

Anthuriums, Alocasias, and most Hoyas are more cold-sensitive and prefer a minimum of 15 to 18 degrees Celsius.

Succulents and cacti from arid regions are surprisingly cold-tolerant, withstanding temperatures down to 5 to 10 degrees Celsius for short periods, though they prefer 15 to 20 degrees Celsius during the growing season.

Tropical ferns prefer a minimum of 12 degrees Celsius.

In practice, most UK homes do not fall below 15 to 17 degrees Celsius in normally heated rooms, even in winter. The main risk zones are unheated spare rooms, conservatories, or positions directly against single-glazed windows on cold nights.

Cold Draught Damage

Brief exposure to cold draughts is often more damaging to tropical houseplants than general cool room temperatures. A cold draught from an opening door or a gap in a window seal can cause rapid cell damage to the leaf surfaces it touches, producing sudden brown blotches or wilting in the affected area even if the room temperature is otherwise adequate. 

Heat Stress

Most tropical houseplants tolerate temperatures up to 28 to 30 degrees Celsius reasonably well, provided they are watered adequately and not in direct sun. Above this range, many plants show heat stress: wilting in the hottest part of the afternoon (recovering in the evening), leaf roll and curl, and accelerated compost drying. During UK heat waves, moving plants away from south-facing glass and ensuring adequate ventilation (open windows) manages heat stress effectively. See our guide on why houseplants droop in heat.

Plants That Benefit from a Cooler Winter

Some houseplants need a cooler rest period to trigger flowering the following season. Phalaenopsis orchids reliably set flower spikes after a period of 12 to 15 degrees Celsius nights in autumn. Christmas Cacti require cool nights and shorter days to trigger bud set. Keeping these plants in a naturally cooler room (a spare bedroom, a north-facing room) from late September to November provides the temperature differential they need. After flower spikes appear, moving back to normal room temperature supports development and flowering.

Frequently Asked Questions

Only if you can maintain a minimum temperature above 12 to 15 degrees Celsius. An unheated UK conservatory typically drops to outdoor temperatures at night in mid-winter and is not suitable for most tropical houseplants from October to March. Options include portable electric heating to maintain a minimum temperature, or moving plants from the conservatory to a heated room for winter and returning them in spring.
In a normally-insulated UK home, a few days without heating in mild winter conditions (above 5 degrees Celsius outside) typically does not cause temperatures to drop below 12 to 15 degrees Celsius indoors. In severe cold or poorly-insulated properties, cold damage is possible. Most plants tolerate brief cool periods without permanent harm; it is prolonged cold that causes damage. A thermometer in the room gives you a reliable picture of the actual temperature range during your absence.
For most tropical houseplants, the optimum temperature for growth is 22 to 26 degrees Celsius, which supports maximum photosynthesis and cell division rates. In practice, most UK homes are in this range during summer and slightly below it in winter. See our guide on winter dormancy in houseplants for how the lower winter temperatures affect growth rate.
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