Ok, I know this post is old now by a few years, but as far as I can tell Sgardner, if you want to grow temperate pings, you need to keep them outside, because they just DO NOT like house conditions. Temperate pings need cool nights as I have just spread some P macroceras seeds and P grandiflora in a clear plastic bin outside and I do not even think anything is germinating. In any case though, you MUST keep them outside and they must get 3 hours of very bright sun which my seedlings are getting now as the sun sets around 9 pm here in montana. I would suggest from what I have seen of any cold temperate pings and growing conditions, is keep them outside protected from mid day sun so they either get 3-4 hours in the morning before 11 am or after 3pm in the afternoon until sunset. The seeds need very cool nights around 40's to 50's to germinate as they actually grow up to the subalpine zones of mountains with very harsh climate and unpredictable weather. The seeds will not germinate in temps above 75F as they do not get that kind of heat except for the 2-3 month growing season in the rocky mountains. The seeds need to be kept around 75F outside, shaded from the hottest sun of the day for at least 3-5 hrs and they can handle sun in the morning or afternoon, but the temp needs to be mid to high 70's MAX for germination and they need to have nights that are at least 10-15F cooler than daytime temps so lets say seeds are 77F during the day, they need to be around 50-60F at night or cooler. They are slow growing plants and they need a montane environment to do well. Humidity needs to be high, but they need fresh air circulation as well. I would leave the plants outside to get full morning sun for 3-4 hrs and then be shaded the rest of the day and hopefully night temps will be 10-15F lower than daytime. Humidity around 45-65% seems adequate although I do not monitor the actual humidity all day int he bin. I would say even if it is 85F here during the hottest part of the day, the plants rarely get above 77F being in the shade and the wind blows a nice cooler breeze so temps do not feel 85F- maybe 75F if that as the evaporating water cools the bin as well. I would guess the temp in about 75F max day and 55F max night. We are still in the mid to high 40's at night but that is good enough for them. They also grow well in very rocky kinds of substrate like serpentine rock mixed with some play sand should be fine, although one guy who sent me some self pollinated seeds said he grew his in pure peat moss and they do fine. Anything that holds moisture, but the plants need to be exposed to VERY cold winter temps at 0F or less in order to properly get through dormancy and they must have ideal conditions in summer to form a strong hibernaculum. They can produce gemmae, but I would not count on that either as they seem to test my patients and limits. Although they are easy to grow because you leave them outside and don't try so hard to grow them. they should be fine outside, but I doubt you will have any success growing indoors as they just need very tough conditions to grow. They have been growing that way for 1000's of years and are used to it. Hope that helps