Plants should be watered early in the morning in Northern California, according to the book "Northern California Gardening." This will allow plants to use water before it evaporates in the sun. Watering in the morning also lessens the chances of diseases and pests that attack plants that are wet and cold for too long, like those watered late in the day.
About this Author
Marie Notnats enjoys learning about new topics and teaching people new skills. She has been writing professionally since 2008. She is a professional horticulturist with a Bachelor of Science degree in horticulture from Brigham Young University. She writes for About.com, Examiner.com, eHow, and assorted gardening blogs.