Hi Jack, with Pinguicula, as with other carnivorous plants, it's important to sow onto a nutrient poor medium. Normal alpine compost has nutrients in which will quickly kill them.
Did you stratify the seed, or did they come up straight away? My experience of temperate Pings is that they generally need a cold period to stimulate germination.
Unlike many carnivorous species,
Pinguicula seem indifferent to pH. Indeed many species grow in quite base-rich environments in nature. Last year I sowed seed direct onto pieces of tufa left standing in plastic trays (and therefore kept wet) with pleasing results - see photos. They are just starting to die back to resting buds now.
I have also been putting my temperate Pings into these black containers made from recycled car tyres - a Canadian company called Tierra Verde makes them. Not terribly cheap unfortunately but they should be water and frost proof. As you can see they hold water. I fill them almost to the top with sharp sand, then place the tufa 'island' in the middle and fill with water. The tufa then stays moist through capillary action and seems to make a good butterwort habitat.
