Plant care
Bacopatemperature & humidity
Sutera cordata
More about bacopa
Ideal temperature for bacopa
Bacopa is comfortable in any room a person is comfortable in, roughly 5–25°C (41–77°F). The mistakes are micro-climates: a north-facing window on a frosty night, a south-facing windowsill in a summer heatwave, the standing draught between an opened kitchen door and the radiator behind it. Read the room around the plant, not the thermostat. Below roughly 5°C the damage starts — soft blackened patches, translucent leaves, sometimes overnight.
Cold tolerance & winter care
Bacopa is frost-tender (USDA 9–11 (grown as annual in zones 3–8), RHS H2). It cannot survive a frost, so in most of the US and UK it lives indoors year-round or summers outside and comes back in well before the first autumn frost — once nights drop toward 10-12°C is the cue, not the first frost warning. Acclimate it over a week when moving between indoors and out so the leaves do not shock.
Humidity for bacopa
Bacopa sits happiest at around 40–70% relative humidity. Appreciates moderate humidity. In very dry, hot air it desiccates quickly and drops flowers. Grouping containers or placing them on trays of damp gravel helps in dry indoor or patio environments. The usual low-humidity tell is crisp brown leaf tips and edges while the soil moisture is fine — a sign the air, not the watering, is the problem. If you need to raise it, the reliable methods are grouping plants together, standing the pot on a tray of damp pebbles (the pot above the waterline, never in it), or running a small humidifier in winter when indoor heating dries the air most. Misting is the least effective — it raises humidity for minutes, not hours.
Bacopa temperature & humidity — frequently asked questions
What temperature is best for bacopa?
Bacopa grows best between 5–25°C (41–77°F). Keep it out of cold draughts, off freezing windowsills in winter, and away from the hot dry air directly above radiators — the extremes matter far more than the average room temperature.
How cold can bacopa tolerate?
Bacopa starts to suffer below roughly 5°C. It is frost-tender and will be damaged or killed by a frost, so bring it indoors once nights fall toward 10-12°C.
What humidity does bacopa need?
Bacopa prefers about 40–70% relative humidity. Appreciates moderate humidity. In very dry, hot air it desiccates quickly and drops flowers. Grouping containers or placing them on trays of damp gravel helps in dry indoor or patio environments.
How do I raise humidity for bacopa?
Group it with other plants, stand the pot on a tray of damp pebbles (kept above the waterline), or run a small humidifier in winter. Misting only helps for a few minutes, so it is the weakest option for a plant that genuinely needs more humidity.
Can bacopa live outside?
Bacopa is rated for USDA zone 9–11 (grown as annual in zones 3–8) and RHS hardiness H2. Outside that range it must come indoors before the first frost — treat any outdoor stint as a summer holiday, not a permanent home.
More bacopa care
In the UK? Keeping bacopa warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full bacopa care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.