In other forums some have reported that this can be caused by having certain structures underneath the biodome including flooring/foundation, various items built like terminals or refiners or using certain types of posts or struts to get the biodome off the ground. Removing these on a trial and error basis was the solution with understanding that you may not be able to put the offending item back after planting.

Suggest saving then keep removing items one at a time and then checking to see if planting now works until you find the culprit(s). You can then use the save to get you back to where you started and either remove the offending structure or move the biodome.