Growing African violets is an adventure that should be tried by all who enjoy indoor plants. If you hit the right formula for success, they are probably the nicest indoor flowering plant we can grow. We can thank Baron Adalbert Walter von Saint Paul-Illaire for finding them growing wild in East Africa in 1894. He took samples home to Germany, where it was given the scientific name Saintpaulia ionantha, and it became an instant hit. African violets have adapted to indoor culture extremely well.
Growing African Violets is like following a cooking recipe. You’ll usually enjoy success, unless you leave out key steps, use wrong ingredients, and cook at the wrong temperatures.
Recipe for a blooming African Violet:
1. Start with a quality plant from the garden center or floral shop. Look for rich green healthy leaves free of blemishes, yellow leaves and droopy stems. Skip plants whose leaves look wilted, especially in winter, as violets are easily and permanently damaged from chilling.
2. African Violets are often sold in pots large enough for continued growth. Sometimes these pots are very thin and warrant replacement. Pot size is important, and the rule of thumb is one-third the leaf-spread diameter. If the plant is 9 inches across in diameter, the pot diameter should be 3 inches.
Violets bloom best if slightly “pot-bound”, meaning its roots have filled the pot. Either plastic or clay pots work, but violet leaf stems that contact the edge of clay pots seem to rot. If clay pots are used, line the top edge with aluminum foil, or dip the pot rim in melted paraffin.
3. When repotting, choose a soil labeled for African Violets. They’re specially blended to imitate the rich organic soil of the tropics.
4. Growing instructions on the plant tag indicate violets need moderate to bright indirect light, which isn’t overly specific. If growing a violet in a window’s natural light we need to adapt to the changing sun intensity of the seasons. In winter when the daytime sun is low on the horizon and weak, violets do well with filtered sunlight directly in a south, east, or west window. 
Direct sunlight from those same windows will be too intense in spring and summer as the sun gains power and longevity. Moderate the intensity with sheer curtains, or move the plant alongside the window.
How can we tell if the African violet is getting “moderate to bright indirect light?” Hold your hand over the violet, and if a strong shadow is cast, then the light is bright enough for violet growth and bloom.
If proper windows are lacking, violets perform very well under fluorescent lights. Two fluorescent 40 watt tubes, cool white, and warm white, produce great blooming violets. Special plant light bulbs work well also. Locate plants 12 inches below the tubes, and provide 15 or 16 hours of light per day. Violets benefit from a daily 8-hour dark period.
5. Watering technique is the recipe‘s most difficult part. Avoid softened water (too high in salts) and chlorinated water (let it sit overnight to evaporate chlorine.) Cold water shocks violets, so use lukewarm or room temperature water.
Avid African Violet growers have personal preferences whether to water from the top or bottom. With both methods, the rules are the same: Don’t get cold water on the leaves, don’t get the inner crown wet because it can stimulate rot, and use room temperature water.
When watering from the bottom, fill the drainage dish with water and allow to remain until the soil surface feels moist, but usually not more than 30 minutes Then discard extra water. Special African Violet self-watering inventions can be purchased mail-order or from some garden centers.
Water when the surface inch of soil is dry to the touch. Violet roots must breathe, so avoid constantly soggy soil.
6. Optimum air temperature for violets is about 70 degrees F. They can easily be chilled below 60 degrees. Keep away from hot or cold air blasts from furnaces or open doors.
7. Humidity is important for continued bloom. Set plants on water-filled trays of pebbles (pots not sitting in the water) to increase local humidity.
8. Treat plants to an occasional helping of water-soluble fertilizer. Miracle Gro will work, but try special African violet fertilizer.
9. A tiny insect called thrips has become an increasingly common pest of violets. They are difficult to see, about the size of a small undotted “i”. Flowers become streaked or distorted. Streaks or blotches form underneath leaves, and leaf edges may brown. Neem oil is recommended. It’s non-toxic to humans, and great for houseplant insect control.
10. Now the most important ingredient: Take time to enjoy a tropical wonder that has adapted so well to indoor culture. – Happy Gardening!
Excellent advice as always Don, thanks!
Thanks!