I have eight red calibrachoa (Proven Winners brand million bells) hanging baskets. All have been treated exactly the same; but all but 1 are starting to yellow and the blooms are turning pink. Two local garden centers have given me conflicting advice, fertilize with Miracid, fertilize with regular water soluble at only half strength each watering, etc. I am afraid to try anything until I have more information.
|Yellowing can certainly be a sign of lack of nitrogen, so fertilizing could possibly help. If the yellowing is mainly on the newer growth, it could also be a sign of needing a more acid soil -- the pH should be between 5 and 5.5 -- so using Miracid or a similar product for acid loving plants might help. If your water is hard, I would definitely use it at the lighter rate each time you water. Also make sure it includes "minors" to provide additional smaller quantites of a variety of nutrients. The foliar feed provides it immediately, whereas you may also want to use a slow release form for an ongoing supply. This plant is a heavy feeder so I would suggest using both. Read and follow the label instructions. This plant also likes heat and full sun, so make sure they are in sun all day or as a bare minimum half a day of direct sun including noontime. Make sure too that the soil they are potted into is well draining, it should stay slightly moist but not sopping wet or saturated and the container must have drainage holes in the bottom to allow excess water to escape. If the plants continue to yellow, I would suggest you work with your local county extension to determine why and then based on that, decide how to proceed.|