>My question is, just how dry should it be kept during the winter ?
Good question, shame aboutthe answer.
P. moranensis is a large group of plants which currently include plants using
this name but which have somewhat different growth preferences.
Some (like those carrying names like "caudata" and "mexicana") are
totally tolerant of wet soil in winter (mine stand in one inch of rain
water all year). Others seem less tolerant of watewr but this varies
from plants that require a damp soil and plants that prefer it
relatively dry. Despite what the books might say, and despite the
advice given by some nurseries (including specialists), I have not yet
found any tender Pinguicula that requires total dryness in winter (or
during dormancy). My plants definately show a readiness to shrink
beyond safe limits if kept totally dry.
Just to complicate life, there is no obvious correlation between dislike (or
liking) of winter wet and whether the plant rests above or below ground.
(Different types of P. moranensis also tolerate different winter minimum
temperatures. Some types will not be reliably tolerant below 12C while others
are happy down to 5C.)
So, I'm afraid the exact preferences for water will depend on which P.
moranensis you have. The various clones or types vary in their needs.
As a guide, my advice is to err on the side of dryness. Do not stand
plants in water during winter but keep them just slightly damp by hand
watering. Watch the plants and add or reduce water if it looks
necessary.
>It's planted in a peat/sand/perlite
>mixture with a thin layer of sphagnum on top, and I
>keep it indoors (19-25 oC) in filtered-light.
Immediately get rid of the Sphagnum. In winter this will encourage rot as it
holds too much water too close to the plant. With the peat/sand/Perlite, I
would suggest at least as much Perlite as the combined Peat and Sand. The
increased drainage this creates will reduce the impact of overwatering.
Filtering the light is only necessary if it's sunlight. You don't need to
filter artificial light. I'm not sure which you meant.
>From the sound of things, your plant is already past saving. Don't
>give up yet
but to avoid further disappointment, assume the worst.
Hope this helps.
Regards
Paul