Quality is determined when the crop is harvested, and not when it is planted.
First the game tests if the crop gets gold quality, if it doesn't it tries again with silver quality. If both fail the crop is normal quality. Quality is also dependent on the usage use of [[Fertilizer]].
The basic formula for finding a gold quality crop (not including fertilizer) is 1% + 2% per farming level. The basic formula for finding a silver quality crop is 2% + 4% per level, though the game must first fail to award a gold quality crop before it will check to award a silver quality crop, so the chances for a silver quality are slightly reduced. The tables below show the probabilities of harvesting each quality of crop. Note that it is possible to reach Farming level 11-13 with buffs from [[#Food|Food]].