>In my experience, day length counts. Pelargoniums don't need a lot of heat,
>but most species like lots of light. In the Northern Hemisphere, now is the
>time of the shortest days and the least amount of daylight. I always have
>my best luck striking cuttings as the days grow longer. When I want to
>propagate a lot, I would even wait until the vernal equinox (March 21-22)
That's one of the few things growers agree upon. :-)
As for rooting in water v. soil v. what-have-you, I've read different recommendations from different sources. Same applies to feeding, except for the nitrogen caveat.
I think there's nothing like one's own experience as guide.