The change from a livestock to an agricultural economy in Livermore Valley began early in the mid-1850's. It was in 1856 that Joseph Livermore fenced in and sowed 160 acres of wheat on his farm in the south-eastern corner of the valley. It is reported that this was the first field of grain ever raised here.

Others noted his success: Samuel and J. West Martin who had bought the Rancho Santa Rita in 1854 in an administrator's sale (it was said that there were enough cattle included in the sale that, when sold, they provided the purchase money for the land) planted wheat in 1857. Joseph F. Black put in 400 acres also that year. In 1858, not to be outdone, Alexander Esdon, Black's neighbor, planted a thousand acres. Hiram Bailey planted 160 acres of grain on his place at the end of North Livermore Avenue. Richard Threlfell leased property in what was known as the "big field" (where the Valley East subdivision and LLNL are presently located). He started out with 400 acres and the next year, planted 1700 acres of wheat. The character of the valley as a grain-producing district was changing rapidly.

Cattle and sheep raising was coupled with disappointment as well as success. Years of plenty were mixed with years of failure. 1855 was a dry year: much livestock was lost for lack of grass. During the winter of 1861/62, prolonged heavy rains caused the whole west end of Livermore Valley to be covered with water from Arroyo Road to the laguna in Pleasanton. Many head of stock drowned. Snow in the Livermore hills lasted until April. Two years of drought followed. The year 1864 was an extremely dry year. Many cattle, horses and sheep, not only in Livermore Valley but all over California, died for lack of pasturage. It has been estimated that the state's livestock population dropped by 50% that year. Sheep were moved to less desirable lands, because they could graze in relatively barren environment. By 1865, agriculture had almost completely pushed out animal husbandry as the chief industry in Livermore Valley.

Agricultural expansion didn't slow down. More and more land was put to the plow in 1866 and 1867. Richard Threlfell now had 4,000 acres under cultivation in the "big field". Alexander Esdon planted 600 acres of wheat on the Bernal Grant and, in addition to the land he was farming on the Dougherty property, he was harvesting a total of 2,800 acres. Wheat and barley were big business.

Grain farmers labored under the disadvantage of being so distant from market that hauling was a large expense item. Until the coming of the railroad in 1869, all the grain in the valley was hauled north to Morris Landing on the San Joaquin River or across the hills to Mowry's Landing near San Leandro. With such tremendous amounts being grown here, one can imagine that the unimproved country roads were well-impacted with traffic summer and fall.