Crown and root rot from overwatering

What's happening

African violets hate soggy soil and water pooling in the crown. When the roots and the dense center of the plant stay wet, they suffocate and decay. The crown goes soft, brown, and mushy, the outer leaves wilt and collapse despite damp soil, and a sour smell often follows as the rot spreads through the whole plant.

How to fix it

Act quickly. Slip the plant out and inspect the crown and roots — if much of the center is already soft and brown, the parent may be lost, so your best move is to take a healthy outer leaf and propagate it: snip a firm leaf with an inch of stem and root it in moist mix or water to grow a fresh plant. If only the roots are affected, cut away every soft, mushy root, repot the firm tissue into fresh, airy mix in a pot with drainage, and water sparingly from below.

This is general guidance based on common symptoms; individual plants vary.