He adds, “When earth is rich it bids defiance to droughts, yields in abundance and of the best quality.” His words reveal a man of the earth far ahead of his time: the scientific connection between fertile soil and plant health is only now being documented.

At Monticello, the gardeners dig plenty of homemade compost and aged manure into the soil, when they can get it. But allegiance to Jefferson’s methods goes only so far.

When flea beetles — known to Jefferson as turnip flies — hit the eggplant seedlings this spring, gardeners sprayed them with insecticidal soap. They will use other pesticides, as benign as possible, to save crops. Now, those eggplant seedlings are hefty three-footers, full of purple flowers.

The intense heat and humidity of a Virginia summer explain why colonial gardens were planted only in spring and toward the end of summer, when temperatures cooled. But Jefferson gardened year-round, planting early in heat-collecting beds along the mountain slope and growing heat-loving crops like okra, melons and tomatoes during the scorching summers. He also grew cool-season lettuces long past their time in the low-lying, damper areas farther down the mountain. (So look for the warm spots around your own garden, as well as the shady, cooler ones, so you can push the limits as he did.)

Jefferson’s biggest mistake was to put his monumental, 1,000-foot-long garden on the south side of this mountain, where it is in full sun from dawn to dusk, with no water source.

The restored vegetable garden here is watered by overhead sprinklers supplied by a 30,000-gallon cistern fed by a spring a half mile down the mountain. If Jefferson’s slaves hauled barrels of water from there on a mule-drawn wagon, there is no known record of it.

We might think that farmers’ markets are new, but the Washington farmers’ market was thriving when Jefferson was in the White House. He avidly supported its farmers, bringing them seeds collected by his consuls in their respective countries, as well as seeds and cuttings from his own plantation, where crops from Africa and the Americas were flourishing.