The latest California Crop Weather report from the National Agricultural Statistics Service’s Sacramento, Calif., Field Office:
The week of May 10 began with a cold and powerful low pressure system that swept across northern and central California and skimmed parts of southern California. Temperatures were as low as 20 degrees below normal following the system which also brought moderate precipitation to portions of California on Monday.
The southern San Joaquin Valley (SJV) felt the impacts of the system by Tuesday as temperatures dropped below normal. By mid-week, the leading edge of an offshore high pressure ridge caused temperatures to increase to near normal levels.
By the end of the week, the ridge amplified and moved onshore causing temperatures to rise a few degrees above average for most of the state. By late Sunday, an offshore low pressure system began to increase cloud cover for northern and central California decreasing daytime highs to near normal.
• Field crops
The winter wheat harvest started in southern California. Wheat was harvested for silage in the SJV. Winter forage harvest continued and was green chopped or cut and baled.
Alfalfa harvest  for hay and silage continued. Most areas have completed the first cutting. The second cutting is underway. Warmer weather aided crop growth.
Oats were harvested in the SJV and corn was planted. Corn plant height ranged from freshly planted to 9 inches high. Cotton fields  were sprayed and cultivated. Rice fields  were cultivated, planed, or flooded. Growers planted as conditions allowed.
• Fruit crops
The picking of Valencia oranges  in the SJV continued normally as the lemon harvest was focused along the coast. The Navel orange harvest continued at a slower pace while the tangerine harvest neared its conclusion in the SJV.
The citrus bloom was completed as preparations for the planting of new citrus trees were undertaken. The cherry harvest volume from early maturing varieties continued to increase.
Harvesting began for early apricot and peach varieties.
Fungicide applications and tree thinning were ongoing in prune, plum, and nectarine orchards plus in late variety apricot and peach orchards.
Fungicide, herbicide, and fertilizer applications along with irrigation were ongoing in grape vineyards in the Central Valley. The SJV blueberry harvest began. The strawberry harvest continued normally. Strawberry plantings were completed in Siskiyou County.
• Nut crops
Some precautionary miticides and fungicide applications were ongoing in almond orchards . Several growers planned to delay applications until hull split due to continued subdued insect development. There was normal nut and leaf drop in almond orchards as the crop showed good development.
Blight and herbicide applications plus irrigation were ongoing in walnut orchards. The walnut, pistachio, and pecan blooms continued toward completion.
• Vegetable crops
The sweet corn harvest  continued in Imperial County with excellent yield and good quality reported. Treatments were applied to the crop to target corn earworm. Melons also developed well.
Garlic and onion growth was good in Fresno County. Carrots looked good and were fertilized. Carrots were treated with herbicide and fungicide.
The SJV tomato crop was irrigated, weeded, cultivated, and fertilized. Fungicides were applied. The growth of vegetables in Tulare County was slowed by cooler weather. The planting of tomatoes, peppers, and squash continued.
In Siskiyou County, producers finished planting the onion crop. Irrigation and weed control were ongoing. Sutter County’s field work, pre-plant herbicide treatments, and ground preparation advanced. The planting of tomato transplants resumed.
Tomato fields were planted in San Joaquin County. The asparagus harvest continued. Asparagus was harvested in Merced County along with the first of the radicchio and parsley crops. The planting of bell pepper, cantaloupe, honeydew, watermelon, and tomato fields progressed.