I had the same problem and I'm in socal also. I would be willing to be that you are using Fox Farms Organic soil. That's why the no nutes yet?
First:
Do you have little tiny flying bugs hangin' around your plants and particularly your soil? They don't start out flying, but crawling on the soil. Those are gnats and for some reason they grow like crazy in that fox farms stuff and it seems we have a shit ton of them in socal. my buddy grew at the same time as me, different setup, different strains, no interaction between his and mine, had the same gnats. Check out for them, and kill'em.
Second:
The FoxFarms organic mix does not have enough Nitrogen in it. When the plants get to be about 4 weeks old they run out. They will continue to yellow and die and won't make it through flowering very well. Add Bat Guano if you are using organics. Mexican Bat Guano is what was suggested to me. It helped me keep them alive long enough to harvest, but they didn't look good at the end. Still defiicient on nitrogen.
Make sure that you pump them up really well with Nitrogen and they should bounce back. Now you have to be careful because they are loaded with other nutes and easy to burn them trying to get enough nitrogen in there. That's why I stayed away from that soil this time.
Good luck!