Fiat, personally I would plant the new bulb in soil. All of mine are in soil and I have had 100 % success again this year with getting them to produce bloom scapes.
About 1 to 1 1/2 inches is fine, have a paper towel handy as you will find a lot of liquid will be released after cutting the stalk, just dab the cut until it stops. This article may be helpful to you.
http://garden.org/ideas/view/m...
