Hey there @Evangeline, welcome to the Discourse! The devs have acknowledged the issue with farming, it is due to the use of 2 different types of AI (one for planting, and another for everything else). A fix is expected in Alpha 14.
For more details, see Yang’s post here:
http://discourse.stonehearth.net/t/inefficient-farming/18363/13?u=jomaxro