Half of the precipitation occurs in the winter months and the remainder during the summer monsoons from July through September. The winter snowpack in the mountains in eastern Arizona provide surface irrigation water that is stored in a series of resevoirs along the Salt and Verde Rivers. A majority of the vegetable crops are furrow irrigated with a small proportion grown with subsurface drip systems. The state ranks in the top ten in the U.S. in production of ten vegetable commodities of which Maricopa County contributes significantly to six of the ten. Potatoes for fresh market and processing are grown on nearly 3,450 acres in Maricopa County.
Substantial acreages are devoted to cauliflower, cabbage, spinach, sweet corn, and radishes.
Other vegetables grown in Maricopa County include lettuces, turnips, swiss chard, oriental cabbages, mixed greens, cilantro, endive, escarole, kale, leeks, parsley, green onions, rapini, and several specialty melons. The majority of the vegetables produced in Maricopa County are shipped throughout the U.S. or consumed locally and premium quality products may go to overseas markets. Most of the melon and vegetables are grown for a specific time period when other parts of the U.S. are not in full production. Some potatoes are produced for local potato chip processing plants.