Since you can't be out in the garden in this weather anyway, you might as well be at the SF Flower & Garden Show. There will be amazing demo gardens and lots of great seminars. There's a big focus this year on edible gardening and even cooking demos from Bay Area chefs. SFGate has a helpful write-up of the highlights and you can get the full seminar schedule on the SF Garden Show web site. The Show runs through Sunday.