Re: [IGSROBIN] Weather report & species.
You said the leaves of your P. transvaalense curled up. I was unsure about
whether that was because you had them on a south-facing window sill or
because the room humdity was very low, night and day.
If it is the location I could suggest you place a reflector to the rear of
the plant to bathe it in more uniform light. Either a picture frame with
alumininium wrap or white glossy paper would help.
If it is too low a humididty level a saucer of water near the plant may work.
San Diego, California