Thomas Jefferson made plans to cultivate cotton and bought seed, but there is little record of how much was planted at Monticello and how well it did. By 1809, cotton was no longer grown in Virginia on a large scale. The growing season was simply too short as compared to the deeper South. It became quite expensive to buy cotton by this point as the U.S. stopped importing it. Jefferson mainly focused on cotton production for home manufacture.
1769 October 1.' "Pd. Mrs. Agey's waggoner for bringg. cotton 4/."
1769 December 16. "Gave Dan. Hutchings (master of the packet) to buy 10. lb. of cotton W. Indain 20/."
1770 January 2. "Gave Mrs. Bolling to buy cotton & pay spinng. 31/."
1774 December 16.' "Bought 3 lb. cotton in the seed of Branford for which I pd. him 1/ & still owe 3 3/4 d."
1774 December 18. "Pd. Branford in full for cotton & chickens 1/3."
1774 December 24. "Pd. old York in full for cotton 3/6. Pd. Cuffy for cotton 2/3."
1775 February 8. "A pint of cotton seed contains of good seeds 900. Consequently a bushel will contain 57600. Put 4. in a hill and it will plant hills 14400. If hills are 2. f. apart an acre will contain abt. 11025. So that a bushel of seed will plan 1 1/3 acres."
1775 April 4. "Gave old York to pay for 3 lb. cotton he bought and 2 lb. more he is to bring from one of Skelton's negroes 7/6."
1775 April 9. "Pd. Skelton's Sam for cotton 2/9."
1775 September 20. "Sent my mother...4 lb. of picked cotton which charge."
1783 January 27. (Jefferson's statement of losses to the British at His Cumberland plantations in 1781). "130. lb. of cotton" 
1806 July 10. (Jefferson to James Bowdoin) "Of tobacco, not half a crop has been planted for want of rain; and even this half, with cotton and Indian corn, has yet many chances to run." 
1808 July 15. (Jefferson to Monsieur Lasteyrie) "The limits within which the cotton plant is worth cultivating in the United States are the Rappahannock river to the north, and the first mountains to the west. And even from the Rappahannock to the Roanoke, we only cultivate for family use, as it cannot there be afforded at market in competition with that of the more Southern region. The Mississippi country, also within the same latitudes, admits the culture of cotton."
1812 January 21. (Jefferson to John Adams) "We consider a sheep for every person in the family as sufficient to clothe it, in addition to the cotton, hemp, and flax which we raise ourselves."
1813 January 12. (Jefferson to James Ronaldson) "But we must acknowledge their [Southern fellow citizens] services in furnishing us an abundance of cotton, a substitute for silk, flax and hemp."
1818 March 20. (Jefferson to Bernard Peyton) "The impossibility of buying raw cotton obliges me to recur to the cultivating it myself. So much has it got out of practice that even the seed is lost in this part of the country. Could you possibly buy me a sack or barrel of about 5 bushels?"
↑ Please note that this list should not be considered comprehensive.