Use the gather plants designation on the whole map. Unless you're in a challenge-worthy biome, you should get more plants than you immediately know what to do with. Repeat every once in a while. In the kitchen submenu of the (z) screen, set the plants to brew only. Set the still on a (r)epeating brew drink job. Go back to the kitchen menu as plants are brewed and make sure that as new seeds appear they are set to cookable. Go to your kitchen workshop and put in (r)epeating meal-cooking jobs. Essentially, you can feed a whole fort off the flora in an average biome by gathering what grows in the wild, brewing it for drink and then cooking the seeds into meals for food. Watch out for job cancellations (which occur when the brewing/cooking exceeds the supply or when you have no barrels or pots to store the drink in) and you're good to go. Note: an alternative to watching out for job cancellations can be to queue up so many brew/cook jobs in the manager screen. In that case you'll just want to queue up more when you find you're running low on food or drink, just like you need to periodically designate more wild-grown plants for gathering.
Yes, this is how I run most of my forts; no, I don't generally embark in particularly challenging biomes; yes, I do try to take some measures to make the surface safe for my dwarves (e.g. restrict them to a hilltop that can only be accessed via raisable bridges, wall off the outside of the map [usually without exploits, because I do like the challenge of doing things legitimately where possible], etc.).