Under Richard Bland Lee's ownership, Sully transitioned from a tobacco farm into a multi-crop operation. Lee applied nutrients and crushed limestone to the worn soil, and made use of crop rotation to increase its productivity. Wheat, rye, timothy, clover, and corn were grown. Livestock raised included cattle hogs, sheep, and horses.
Fruit-bearing cherry trees lined the driveway approaching the main house. Sully's orchard produced apples, peaches, plums, quinces, apricots, and pears. A two-acre kitchen garden supplied a variety of vegetables. Completed in 1801, the stone dairy provided cool storage for eggs, milk, butter, and cheese.
Sully's farming operations were overseen by a farm manager who carried out Lee's instructions. The work was done by enslaved laborers and some indentured servants. A 20th-century archaeological excavation found evidence of three structures (part of an early slave quarter) along Sully's south road.