I have a garden full of carnation this year, from seeds I started last year. They are just gorgeous, all different kinds, all different colors. My question is, how to preserve them best as cut flowers. Mine seem to wilt within hours, in a vase, and I know the ones you buy at florists seem to last for weeks. Is there any special technique peculiar to garden grown carnations that would make them a bit more long lived in a vase?