Have you ever wondered why mid season containers start looking a bit sad? Maybe you have noticed that the blooms just aren’t coming on as strong as they did earlier on. Or maybe even the plant itself is looking a little tired. Plants in containers are in a somewhat challenging spot to start. Usually the soil space is limited and as the plant grows roots take up more space and nutrients become scarce. All plants, but especially container grown will benefit from a good meal every now and then. Just like us they need nutritious food to flourish.
When we plant up containers in spring we add a slow release fertilizer to the soil before planting. Each time the plant is watered, it’s gets a good shot of food as the slow release slowly erodes. This nutrition lasts for about 2 to 3 months. If we have a really wet year, the slow release pellets will not last as long. After that, containers benefit from a boost of fertilizer. You can use a soluble fertilizer, like Miracle Gro or you can go ahead and reapply another shot of slow release pellets.
I still recommend watering with a fertilizer every two weeks even with a slow release in the soil. It won’t hurt the plant. It will optimize bloom. One thing to watch out for is if your plants are really dry and wilted. Do not water them with fertilizer. They may burn. As always, it's better to water early in the morning so the soil has a chance to dry out.