The California Crop Weather report from the National Agricultural Statistics Service released on May 4:
A weak high pressure ridge over California quickly gave way to an upper level low pressure system which moved over Oregon at the start of the week (April 27). Cool but dry conditions prevailed over most of California for the first few days.
Only isolated light showers fell across the coast and mountain areas of extreme Northern California, and in the Northeast Plateau. This pattern persisted through the middle of the week for Northern California while high pressure gradually rebuilt over the south.
Unseasonably cool temperatures were the result across the northern two-thirds of the state, while Southern California saw temperatures warm to normal levels.
By Friday, subtropical moisture was drawn into the circulation of the upper level low pressure, resulting in widespread shower activity across Northern California; Southern California only received light precipitation.
The remainder of the weekend was relatively mild with continued showers falling across the north, while Southern California remained dry.
Cooler weather this week slowed the growth and development of grain and silage crops. Wheat harvest was expected to start in the next two to three weeks in the Imperial and San Joaquin Valleys. In the San Joaquin Valley (JVC), wheat yields will be reduced for some growers due to lack or water.
Rice planting was in full swing across the state. Previously seeded fields were ready for warmer weather. Some rice fields is the Sacramento Valley will not be tended due to the sale of irrigation water for permanent crops.
Sunflower and bean planting also took place in the Sacramento Valley; sunflower and safflower were beginning to emerge. Alfalfa was cut and baled for hay statewide, along with other forage crops.
Sugar beet harvest began in the Imperial Valley. Corn and cotton fields continued to be planted; weed spraying in corn continued. Sweet potato transplanting and hog bed digging continued in Merced County.
Grape vine growth along the north coast slowed due to unusual fluctuations in air and soil temperatures. Leaves were thinned in vineyards to increase sunlight penetration and airflow. Grape vines bloomed in the SJV. Fertilizer applications were prevalent throughout the state for all crops.
Strawberry harvest continued in the Sacramento Valley, and cool growing conditions allowed strawberries to last longer on the plant in the SJV. Blueberries and boysenberries continued to mature. Weed control continued for prune, peach, apricots and nectarines. Fruit set appeared positive for orchard crops, and fruit thinning was still underway in some orchards.
Rain hindered early variety cherry harvest for Royal Champagnes in the SJV. Navel orange harvest was mostly complete, and Valencia orange harvest picked up. Lemon and grapefruit harvests continued.
Irrigation was prevalent in citrus groves due to strong winds and declining soil moistures. Harvest was almost complete for Murcott tangerines and Minneola tangelos. Olive trees began to bloom in the SJV.
Walnuts were treated for blight and sucker control. The almond set was fair, and spring rains helped with mite control. All nut crops were irrigated and fertilized in the San Joaquin and Sacramento Valleys. Pistachios finished bloom and nuts began to set on trees in the SJV.
The planting of processing tomatoes continued in Colusa County. Tomatoes were transplanted in Stanislaus County, where melon planting also occurred. Imperial County experienced winds which prevented bees from effectively pollinating, slowing down the crown set of cantaloupe and watermelon fields.
In Fresno County, blooming tomatoes were fertilized, cultivated, and irrigated. Onions were treated with fungicide to prevent downy mildew and carrots were cultivated, irrigated, and treated with herbicide. Garlic was fertilized.
The spring harvest of radicchio began in Merced County where the asparagus harvest also progressed. Kern County began harvesting lettuce, along with planting acres of tomatoes and peppers. Organic vegetables were growing well.
Although the quality remained good, squash harvested in Tulare County slowed slightly due to cooler weather. Cucumbers were gaining sized and early planted melons began to emerge. Ground preparation continued for future plantings of summer vegetables.