Have you planted them outside in the ground, if so, it is very early for them to be coming up unless you are having very warm days and nights already.

They are still in the package they came in on a shelf. They shelf does receive some light, and I think that is why they have taken off growing. In my area you can't really plant stuff out until mid-late april. How should I stifle the growth. I do have a grow light that I could put them under if they are determined to grow.

If i were you i would put them somewhere dark and cool so as not to encourage growth like in a cupboard somewhere.

T would pot them up and put them in a protected area mine are growin in pot in a water tub will plant them when it gets warm same as calladiums