Question
I have s. purpurea ssp. purpurea and s. luco seeds that I'm putting outside here in Wisconsin. Is it ok for the peat moss and seeds to freeze or should I try to keep them warmer?

Answer
Hello Jason,

Ideally, you will want cold weather down to just above freezing. Pots do not insulate as well as the ground and there simply is less plant cover and material for seeds to fall into in a pot for insulating purposes. You can place a cloth over the pot and then place some mulch or other insulating material over them and around the pot so you won't lose the seeds in the mulch yet they will remain slightly warmer. You can also place them in a cold garage or cold window in your home so long as the temperatures stay around 40 degrees where the pot is located. You will also want them to remain moist all the time. If you keep them indoors or in a garage, mist them slightly once a day. If outside, lift the covering mulch and mist them only occasionally as the mulch will hold in moisture. The problem associated with keeping them covered is mold. Even in a refrigerator or in cold weather, mold is an everpresent danger for any dormant or dead organic matter.

I stratify seeds with minimal complications in an ice chest with a pot of moist sphagnum moss surrounded by frozen water bottles. About 4 bottles around two 4-5 inch pots works well to keep the temperature down to about 40-50 degrees and the ice chest can be opened by day to air it out and place it in sunlight to kill mold. By night I replace the bottles and cover it (replace the bottles day and night on a 12 hour cycle). I have never lost a plant in dormancy nor had any complications with mold in such a setup. I have had mold problems trying to stratify in the refrigerator. Another benefit of an ice chest is that you can leave the pots open and place damp paper towels under them to keep up moisture. They will not dry out like they will in the fridge.

In any event, whatever method you use should keep the seeds just above the freezing point of water (32 degrees) and allow some air circulation and sunlight in to keep down mold. Covering or containing the seeds for lengthy periods without open air circulation tends to enhance conditions for mold growth.

Make sure you only sprinkle the seeds on top of the sphagnum moss and never push them down or plant them in holes in the moss. Carnivorous plant seedlings tend to fall directly on top of the ground and do not get covered by much plant matter, other than the closely growing parent plants and their dead leaves, in the wild. They are small seeds and the seedlings will be tiny, so cannot grow to the surface before running out of energy. If you want, you can granulate some moss in a sifter and place a very thin layer over them to enhance moisture absorbtion in the seeds, but it is not necessary if you mist them once a day and keep the moss moist all the time.

Christopher