First, batteries are expensive and don't last too long. This cost has definitely driven me out of the off-grid growing experiment. The electric company turns out to be cheaper than solar for my small application.
Second, without an expensive inverter, DC parts are hard to find and don't last. Again, AC seems to be the way of the world.
Finally, the solar panels always seem to be in the way! Unless you have a LARGE area or a roof to place your panels, expect to feel your style cramped by the panels where otherwise good garden space could be utilized.