When Washington became a farmer, but one system of agriculture, so far as Virginia was concerned, existed, which he described long after as follows:
Knowing no better, Washington adopted this one-crop system, even to the extent of buying corn and hogs to feed his hands. Though following in the beaten track, he experimented in different kinds of tobacco, so that, "by comparing then the loss of the one with the extra price of the other, I shall be able to determine which is the best to pursue." The largest crop he ever seems to have produced, "being all sweet-scented and neatly managed," was one hundred and fifteen hogsheads, which averaged in sale twelve pounds each.
From a very early time Washington had been a careful student of such books on agriculture as he could obtain, even preparing lengthy abstracts of them, and the knowledge he thus obtained, combined with his own practical experience, soon convinced him that the Virginian system was wrong. "I never ride on my plantations," he wrote, "without seeing something which makes me regret having continued so long in the ruinous mode of farming, which we are in," and he soon "discontinued the growth of tobacco myself; [and] except at a plantation or two upon York River, I make no more of that article than barely serves to furnish me with goods."
From this time (1765) "the whole of my force [was] in a manner confined to the growth of wheat and manufacturing of it into flour," and before long he boasted that "the wheat from some of my plantations, by one pair of steelyards, will weigh upwards of sixty pounds,... and better wheat than I now have I do not expect to make." After the Revolution he claimed that "no wheat that has ever yet fallen under my observation exceeds the wheat which some years ago I cultivated extensively but which, from inattention during my absence of almost nine years from home, has got so mixed or degenerated as scarcely to retain any of its original characteristics properly." In 1768 he was able to sell over nineteen hundred bushels, and how greatly his product was increased after this is shown by the fact that in this same year he sowed four hundred and ninety bushels.
Still further study and experimentation led him to conclude that "my countrymen are too much used to corn blades and corn shucks; and have too little knowledge of the profit of grass lands," and after his final home-coming to Mount Vernon, he said, "I have had it in contemplation ever since I returned home to turn my farms to grazing principally, as fast as I can cover the fields sufficiently with grass. Labor and of course expence will be considerably diminished by this change, the nett profit as great and my attention less divided, whilst the fields will be improving." That this was only an abandonment of a "one crop" system is shown by the fact that in 1792 he grew over five thousand bushels of wheat, valued at four shillings the bushel, and in 1799 he said, "as a farmer, wheat and flour are my principal concerns." And though, in abandoning the growth of tobacco, Washington also tried "to grow as little Indian corn as may be," yet in 1795 his crop was over sixteen hundred barrels, and the quantity needed for his own negroes and stock is shown in a year when his crop failed, which "obliged me to purchase upwards of eight hundred barrels of corn."
In connection with this change of system, Washington became an early convert to the rotation of crops, and drew up elaborate tables sometimes covering periods of five years, so that the quantity of each crop should not vary, yet by which his fields should have constant change. This system naturally very much diversified the product of his estate, and flax, hay, clover, buckwheat, turnips, and potatoes became large crops. The scale on which this was done is shown by the facts that in one year he sowed twenty-seven bushels of flaxseed and planted over three hundred bushels of potatoes.
Early and late Washington preached to his overseers the value of fertilization; in one case, when looking for a new overseer, he said the man must be, "above all, Midas like, one who can convert everything he touches into manure, as the first transmutation towards gold;—in a word one who can bring worn out and gullied Lands into good tilth in the shortest time." Equally emphatic was his urging of constant ploughing and grubbing, and he even invented a deep soil plough, which he used till he found a better one in the English Rotheran plough, which he promptly imported, as he did all other improved farming tools and machinery of which he could learn. To save his woodlands, and for appearance's sake, he insisted on live fences, though he had to acknowledge that "no hedge, alone, will, I am persuaded, do for an outer inclosure, where two or four footed hogs find it convenient to open passage." In all things he was an experimentalist, carefully trying different kinds of tobacco and wheat, various kinds of plants for hedges, and various kinds of manure for fertilizers; he had tests made to see whether he could sell his wheat to best advantage in the grain or when made into flour, and he bred from selected horses, cattle, and sheep. "In short I shall begrudge no reasonable expence that will contribute to the improvement and neatness of my Farms;—for nothing pleases me better than to see them in good order, and everything trim, handsome, and thriving about them."