Growing Healthy African Violets
The Root of the Issue

By Terri Vicenzi Bloomington, Indiana
First published in the African Violet Society of America magazine

As an experienced grower of African violets, Streptocarpus and other gesneriads, I have had the typical ups and downs that come with caring for a large plant collection. However, in the past couple of years, I have had a persistent problem of root rot with my African violets. The problem manifests itself in the mature outer leaves becoming slightly yellow, followed by the formation of a dark, soft spot where the petiole attaches to the leaf blade. Shortly thereafter, the entire leaf
turns dark brown.
The roots on my violets are plenti­ful, but their tan-to-brown color­ation is another sign that all is not well. The plants otherwise appear healthy and bloom regularly, but after several months of this behav­ior, the plants eventually perish. This is clearly a slow and insidious case of root rot, but what was I doing wrong? I wick water, repot at least two to three times a year, and I use good sanitary practices during repotting and cleaning. I have tried
everything — several different (and expensive) chem­ical fungicides, modifications in the amount of per­lite in the soil mix, alternate wicking techniques, and more frequent repotting. Even with the tried-and-true crown resuscitation method championed by Joyce Stork, my restored plants would begin to suc­cumb to the ravages of rot several months later.

Help from a Friend
As an experienced grower of African violets, Streptocarpus and other gesneriads, I have had the typical ups and downs that come with caring for a large plant collection. However, in the past couple of years, I have had a persistent problem of root rot with my African violets. The problem manifests itself in the mature outer leaves becoming slightly yellow, followed by the formation of a dark, soft spot where the petiole attaches to the leaf blade. Shortly thereafter, the entire leaf
turns dark brown.

Photo 1 My PH test strip comparison. The A strip measured tap water; B, fertilizer water; and C aged (reservoir) water

The roots on my violets are plenti­ful, but their tan-to-brown color­ation is another sign that all is not well. The plants otherwise appear healthy and bloom regularly, but after several months of this behav­ior, the plants eventually perish. This is clearly a slow and insidious case of root rot, but what was I doing wrong? I wick water, repot at least two to three times a year, and I use good sanitary practices during repotting and cleaning. I have tried everything — several different (and expensive) chem­ical fungicides, modifications in the amount of per­lite in the soil mix, alternate wicking techniques, and more frequent repotting. Even with the tried-and-true crown resuscitation method championed by Joyce Stork, my restored plants would begin to suc­cumb to the ravages of rot several months later.

Signs of pH Problems
In my investigation, I learned that another subtle sign of a pH problem is the color of the underside of the foliage. Many of my violets' leaves exhibited an uneven purple coloration on the back side of the leaves, which isn't normal, with the noted exception of red-reverse varieties. After consulting Doctor Optimara, I learned that low pH in the soil will inhibit the absorption of many nutrients, including phos­phorus. Phosphorus also is an essential element for healthy root production.
This was the first significant "aha moment" I have had in quite some time. So, I have modified my prac­tices to change out the reservoir fluid monthly. I also am adding a pH-buffering solution to increase the initial pH of the fertilizer water to 7.
It has been 6 months now, and I have noted with delight that I now have plump white roots being pro­duced on plants that previously had dark roots (see photo 2). Young, newly wicked plants are growing better and I'm removing fewer unhealthy leaves. It's still too early to tell if this is the silver bullet, since cultural issues are generally a combination of factors. But it definitely feels like a big step forward in the right direction. Most importantly, thanks to the help and expertise of my friend, I am throwing out a lot less plants.

Photo 2 Roots on a Wicked violet, 2 Months after PH adjustmentand cultural changes. Note the white rootsemerging against the older dark ones.