Spade is a World of Warcraft addon that makes it easier to manage your farm at the Sunsong Ranch. It lets you plant crops (using seeds or seed bags), and use farm tools without having to find them in your bags (or put them on your action bars) — simply right-click on a soil patch to till it or select a seed to plant, and right-click on parched or infested plant to tend to it.
Spade also keeps track of what's growing on your farms, and will notify you when you log in if you have crops ready for harvest. Use the /spade slash command to bring up its interface, and use the cogwheel icon in its header to change Spade's behavior.
Note: Spade uses OPie to present your available seeds/seed bags; you'll need to download and install OPie to be able to select seeds/seed bags using Spade. Spade's plant tracking and farm tools functionality does not require OPie.