You can get gear for your Disciple of the Hand/Land classes from either the market board, or from vendors (or craft it, if you have access to the materials and the required levels). For example, the NPC Domitien with the tag <Independant Tailor> in Old Gridania's market area will sell you gathering gear. His low level stock seems to have stats for both on it, but for a gathering class, you'll want pieces with Gathering and Perception.