plant means to start the germination process. For example this month on the 13th I have an appointment at the hospital where I will be out all day, so I will plant all of the seeds into a dry mix and at 9am my wife will water them for me. Once the seed makes contact with moisture the germination starts.
Biodymanics is an extention of organics. It is pretty heavy and involved stuff but the planting days have always been pretty good for me.
The dates dont fully coincide with the farmers almanac but it is just "each to his own" i suppose. Some dates line up but others dont.