Black Leaves on Houseplants After a Day Outdoors: Sun and Heat Damage

Cause

Intense outdoor sun and heat caused sunscald. One side was more exposed, hence asymmetric damage. Plants root in place; they don't adapt to sudden environment changes.

Action

1. Remove all blackened leaves (they won't recover).
2. Keep plants indoors permanently.
3. New growth will be healthy if light and water are appropriate.

Prevention

If you must move plants out, acclimate over 2+ weeks: start in full shade, add 30 min daily sun. But most houseplants are happiest staying inside.