I have many (10+) containers of impatiens growing in dappled shade. The soil is Miracle Grow. I have been fertilizing with a high bloom fertilizer (15-30-15) every two weeks. Over the past week three of the containers have really slowed blooming and are not prolific as they were. I am in Lindsay, Ontario and the weather has been hot and humid with relief this week. I am curious as to why this would happen with only some of the container.
Thank you for contacting the Toronto Master Gardeners with your inquiry.
After our long drab winter, nothing adds colour to the landscape like hanging baskets and a patio full of containers of blooming in all their glory.
Unfortunately, late July and August seems to be the time when many hanging baskets start to fade. There are a number of key factors that you can do to keep your hanging baskets blooming and beautiful.
- Fertilize on a regular schedule ( which you are already doing) because container and potting soils don’t contain a lot of nutrients, you need to fertilize regularly to keep your plants vibrant. Without the addition of additional fertilizer your baskets will begin to fade. Hanging baskets have limited soil fertility; everytime you water, those nutrients are leached down through the soil and absorbed by the roots. By fertilizing your plants every two weeks, keeps the plants blooming. Too much fertilizer and the plants will become root-bound in their pots. The ideal time to fertilize is immediatelyafter rain or right after watering. This opens up the roots and soil so that they can take uo the much needed nutrients.
- Consistent watering is the second key to healthy baskets. One should get in the habit of watering your baskets at the same time every day. The best time to water is in the early morning so that they can withstand the heat of the day.
- Removing spent blooms helps the plant to spend its energy on making new blooms. If you are growing New Guinea Impatiens, they are self cleaning and do not need to be dead headed.
Sometimes, no matter what you try, a plant becomes too root-bound and cramped. Are the 3 containers that are under preforming smaller than your other planters? If so, you can replant these root bound flowers into a larger planter. The addition of some much needed soil will give the plants the boost they need to put out blooms.