Thomas Jefferson- Experimental Gardener

All Things Considered:

After Jefferson retired from public life to his beloved Virginia hilltop plantation, the garden "served as a sort of this experimental testing lab where he'd try new vegetables he sought out from around the globe," says Peter Hatch, the estate's head gardener. Hatch recently wrote a book about Jefferson's garden and its history called A Rich Spot of Earth.
  Somehow, the author of the Declaration of Independence and the nation's third president found spare time to meticulously document his many trials and errors, growing over 300 varieties of more than 90 different plants. These included exotics like sesame, chickpeas, sea kale and salsify. They're more commonly available now, but were rare for the region at the time. So were tomatoes and eggplant.
In the nearby South Orchard, he grew 130 varieties of fruit trees like peach, apple, fig and cherry.
All the time, he carefully documented planting procedures, spacings of rows, when blossoms appeared, and when the food should come to the table. Behind Jefferson's "zeal to categorize the world around him" was a patriotic mission, Hatch says.
Jefferson wrote, "The greatest service which can be rendered any country is to add a useful plant to its culture."

Jefferson was definitely a fascinating guy.  Like Washington, he did a lot of agricultural and horticultural experiments.  Of course, I bet it is a lot easier to keep a nice garden with a bunch of slaves around to do all the hard work.  My garden fell victim to a couple of dry summers and then a few summers where I was thirsty.