Question: A white crust has appeared on the soil surface of my plants, as well as “brownish crystals” on the leaves in the center. The crown of one plant has rotted. I wick-water and use a soil mix containing one-third perlite.
Answer: These are some of the symptoms of a violet that is being kept too wet. Though convenient, wicking is no better than any other method of watering. Unless done properly, violets will be no better off than if watered by some other means. Judging by the volume of phone calls we get, improper wick-watering practices is one of the most common problems among hobbyists.
As for the white crust on the soil surface, this is another disadvantage of wick, or other methods where water is supplied from the bottom of the pot. When wicking, water is fed into the soil through the bottom of the pot via a wick, then works its way up to the top soil surface. Because of this, anything in the water will also work its way to the soil surface and, if not consumed by the plant, remain there. This crust is either (or both) excess fertilizer salts or minerals found in the water used. Usually this is only unsightly but, if ignored, can become a problem, possibly burning and/or rotting off petioles or even the plant’s crown. Because of this, it is a good practice to regularly repot plants to eliminate the excess minerals and salts with the old soil. Occasional leaching of the soil is also recommended. Top water plants thoroughly so that minerals and salts are washed through and out of the pot bottom.