When it comes to Hedychium and Zingiber I feed them heavy. After the winter I throw away 1/2 to 2/3 of the plant to have room in the pots (20 litre) again and fill up with fresh compost with added organic fertilizer. Once growing I feed every 1-2 weeks with a common mineral fertilizer: I need speed otherwise they will not bloom in our relatively short and cool season. Overwintering I do in a cool room, outside is a certain death (winter can in some years go down to -20C, thats roughly 0F).
Cautleya and Roscoea on the other hand are winterhardy overhere as long as they are well drained.
Ruud
