Your plants are likely just taking their time in acclimating to their new home. Give it some time and try to resist the urge to poke around and prod the soil in checking on them…always seems to result in more damage than good. Chances are that they’re doing just fine.
You may not see much this first year, best to just leave them alone and get established. If all goes well, you’ll be able to cut a handful of spears next year and the year after that hopefully you’ll have more than you can use!