Re: When does spring build-up start in northern California?
Ca is huge. I only know about the areas where my bees will or may sit. Up here, I'd call spring start when the wild mustard seed is blooming. That should be in early to mid Feb, but who knows this year with no rain. depending where you are will get you swings in flow. But it's done for me with the end of star thistle in August.
If you have strong bees and are feeding sub now, they can swarm as early as almonds in Feb. I'll see balls-O-bees in trees then. Like Frank said, usually in March and April. I lost a swarm last year in May and one in June. These were both my fault.
Northern Ca. Zone 9b. Third year newb.