Hi greenzgurl, welcome to Orchidboard!
You are better off putting the stem in water and treating it like any other cut flower, as I don't think putting it in soil will make it do anything. Orchid spikes don't grow roots as far as I know!
Depending on how far along the buds are, you might get them to bloom. Be sure to change the water regularily.
Also, one other thing: you mention soil. Is your phal potted in soil? If that's the case you really should repot it asap into something more appropriate, like a bark based mix. Orchids need lots of air around their roots.
Hope that helps!