Fill the Barn is a card game in which players earn money by planting and harvesting crops to the barn. The game board is a barn with only enough room for three harvests each of six different crop types. Each harvest of a same crop pays a lower price than the previous harvest of that same crop. Once all three harvests of a crop have been filled, players may not harvest any more of that crop type.
In addition to planting and harvesting, players may fertilize a crop to increase its value, or irrigate to protect against drought. Drought or Bugs cards may be played to wreck your opponents' crops while they are still waiting to be harvested. Mice, Junk, and Clean-up cards add a further wrinkle by allowing players to change the availability of crop spaces within the barn.
As the barn fills up, the competition increases to outmaneuver opponents to fill the last remaining crop spaces, with an extra bonus paid to the player who "fills the barn" by harvesting the last crop to fit in the barn. The game ends when either the barn is filled, or when the 115-card deck has been exhausted, whichever comes first.