Q.Impatiens
After transplanting young impatiens, some of them begin to rot off at the ground level of the stem. We live in southern Florida. I usually plant in Oct. & Jan. I even use new potting soil sometimes. What is my solution? I was told this could be snails. But poison doesn’t help. This has been happening every year, for many years.

Certified GKH Gardening Expert
Are you noticing any white coating on the plants as well? I ask because these plants are very susceptible to downy mildew, especially in your area. It also overwinters in the soil, which would explain why it happens each year. Here is more information: https://www.gardeningknowhow.com/ornamental/flowers/impatiens/impatiens-downy-mildew.htm