Andrew, San Diego is very much like the region it comes from temperatures wise. There are other Sinningias that comes for drier regions but this is not the case. Rainfall in the wild for S. tubiflora can be 900-1300 mm. distributed along the year with not really a drought/desert like period. It must be low temperatures that force it to winter dormancy rather than drought. And, large containers or the ground make it produce a few large tubers each year, not the myriad of tubers of all sizes one reads described all the time.