A farm plot is a building that allows dwarves to grow plants from seeds. Plants can be used for food or to brew alcohol. Farm plots built above ground are not suitable for the crops grown on subterranean farm plots and vice versa. Farm plots only display the kind of crops that they are able to grow when selected.
Each farm tile requires a single seed to be planted. Unfertilized farm tiles can produce a stack of 0-6 plants when harvested, depending upon the skill of the planter and random chance. Fertilizing a farm plot boosts production by 1-3 additional plants per stack each harvest.
To fertilize a farm plot, one needs potash, which is produced by processing ash. Each plot must be re-fertilized each season, and the fertilizer must be in place at the time the seeds reach maturity. It does not matter whether the plot is fertilized at the time of planting.
Farming (Fields) labor is required to apply fertilizer. Seasonal fertilization can be turned on, in which case the plot will automatically fertilized in the beginning of a season.