Two of my African Violets have stunted, misshapen leaves in the middle of the rosette. I have encountered the problem in the past, and usually, I just throw the plant away. This time I thought I would try to start new plants from leaf cuttings, but first wanted to be sure the leaves were not diseased or infested.
Plants with this type of stunted growth can have an infestation of spider mites. Oh my! I have battled these little pests on other plants. I took a look at the violet in question with a magnifying glass, but did not see any pests.
A few other causes I found were:
Cool temperatures – Yes, we keep our house rather cool in the winter
Too little light – Yes, I did move them to a window with very late afternoon sunshine.
Too much fertilizer – Could be, but it would be from pre-fertilized african violet soil, not from anything I add. From now on I’ll try to water from the top with a squirt bottle. By using this technique I will avoid getting the leaves or crown of the violet wet, and salts and other toxins in the soil will be washed out the bottom.