Unable to plant crop in space

Hey all, wondering if this is a bug, something new in the updates, or I am just missing something. Created a base in space and walled in a large area for a garden. I put grow lights two blocks up on the ceiling point down upon the soil plot blocks. When i try to plant either pumpkins, durins, or tomatos its giving me a "This plant cannot grow here"

Screenshot here;
http://steamcommunity.com/sharedfiles/filedetails/?id=673149534

I did it in previous versions but couldn't find...

Unable to plant crop in space