Even though I put a good slow release fertilizer in the container at initial planting time, I always use a bloom booster (water hose application) starting now until end of season, every 2 weeks. You should see some quick results if you aerate 1st. Hanging baskets that are shallow or smaller than 14 " diameter will bounce back nicely from the compact soil conditions. I guess aeration also has a lot to do with more oxygen to the roots.
