I've been propagating African Violets for some time. I've noticed that when potting leaves that sometimes 100% make it just fine and other times I can lose over 50% to rot. Usually a part of the leaf starts to rot, rather than the petiole, but sometimes the petiole may start the problem.

I'd like to know a couple things. First, exactly what pathogens are usually responsible for this type of rot?

Second, where do these pathogens reside - I guess I really want to know what I can do to avoid them.

Thank you.

Dear Ann,

There are several factors that influence how the success of propagation. Age of and the condition of the leaves, time of year, air and propagation media temperatures. Typically, you want to propagate from plants that have been actively growing, in a good light situation. Leaves should be healthy with no signs of decline or condition issues. Be sure to use new or sterilized pots or trays to propagate into and that the propagation media (soil mixture) is also brand new and is really soil-less. Be sure that anything you transfer soil with is also clean/sterile. The decay organisms survive on old containers and trays, on the tools that you use and in mixes that actually contain dirt/soil that have been contaminated. Monitor your watering very closely and never let the media stay too wet. Many of the pathogens that cause the decay you describe are water born and spread in the free moisture. When you have open cuts or damaged tissue, the pathogen can move quickly into the propagation material if the conditions for disease are present.

I hope this is helpful.

Sincerely, Richard Hentschel