You don't have to spray herbicide, but it sure does help control weeds. After a plot is established, herbicides can keep it going longer by eliminating the weeds. Mowing can work, especially on small plots, but it does depend on the weeds present (perennial weeds are tougher to control by mowing).

Fertilizer can be applied at planting. Lime takes over 1 year to fully neutralize soil acidity. That said, you can plant grasses (corn, winter rye, oats) while waiting for the lime to work. If you are close to the optimum pH (0.3 or less from ideal pH) but need a little lime, you could go right into whatever you intended to plant.

Take a soil sample, and send it to a local lab (see link) http://ag.udel.edu/other_websites/DSTP/forms1.htm Growing food plots can be a lot of fun, if you are willing to do some research and some work,