You can either use peat + a lot of coarse perlite OR
Good quality sphagnum moss and repot the plants firmly
Don't use tray method to hold water under the pots EXCEPT your plants are very healthy and grow vigorously while you need to water almost everyday. Otherwise you will soon know what root rot is ~
For plants that aren't having a lot of roots, use smaller pots.
Repot them when they started to grow well ~
Put plants in plastic bags is good in dry winter time BUT avoid direct sunlight as it can be dangerous ~
Bright light is good for the plants. Don't put them in heavily shaded places ~
When temperature and humidity rise in spring, try to remove the plastic bags GRADUALLY instead of taking them out right away. However, if the humidity of your growing area is simply too low, they will never pitcher well although the plants won't die ~