Help plants thrive with an application of fertilizer rich with the nitrogen too often in short supply in San Diego soils. Nitrogen content is indicated by the first of the three numbers on a fertilizer bag; pick one with more nitrogen (N), than phosphorus (P) (the second number) or potassium (K) (the third number.)
Scatter fertilizer granules lightly and evenly at the edge of the plant's rootball or foliage-drip line, scratch it into the ground taking care not to harm feeder roots, and then water lightly if soil is not moist from recent rain or irrigation. It's tempting to fertilize when rain is forecast, but heavy showers could carry granules away in runoff.
A new layer of mulch will help build organic content in the soil, but at a slower pace. Mulch also will help hold moisture in the ground as temperatures start to climb. For container plants, a time-release fertilizer is a good choice to keep nutrition high in the limited amount of soil available to the plant.