This beautiful flowering plant in the Gesneriaceae family is well loved for its colorful blossoms and completely symmetrical form. Previously classified as Saintpaulia, these plants have been renamed as the Saintpaulia section of the Streptocarpus subgenus Streptocarpella after genetic analysis. They are easily grown indoors as a houseplants and bloom almost continuously with appropriate care.
African violets need bright, indirect sunlight, preferably from an eastern or western window exposure. They are also easily grown under artificial light but will require more hours of light than under natural conditions. Full direct sunlight is too intense, such as from a southern sun exposure. In nature, plants grow under a deep forest canopy, much like light coming in through a bright sunlit window draped with sheer curtains.
They grow best in temperatures between 65º and 80º F. In summer, plants will accommodate to natural temperatures above 75º F but will cease to grow if temperatures rise near 90º F. African violets dislike cold drafts, so protect them from windowsill drafts in winter.
Since African violets have tiny roots, they need to be evenly moist. Water thoroughly with tepid water either from above or below, taking care not to wet the foliage. Allow the top 1/2" of the soil to dry between waterings. If temperature in the room falls below 60 degrees for more than a day or two, reduce frequency of watering, permitting a full inch of medium to dry between waterings.
After 15 minutes, discard all excess water that the plant has not taken back up. Thorough top watering removes excess salts via drained water. When bottom watering, the soil may take a couple hours to take up moisture, then remove any remaining water from catch saucer. Too-wet soil can cause a fungal disease called stem and crown rot or root rot, which causes wilting. To prevent this problem, water only the soil. Use a long-stem watering can and keep the water away from the plant stem as much as possible. Water early in the day, never at night. Use room-temperature or warm water--never cold.
In addition, if plants appear very dry or are wilting, definitely do not flood the soil right away. A very dry root system cannot absorb the water well, as the root system needs time to plump up before the plant can take up water again. Start by adding 1 tablespoon of water on the soil surface every hour until the soil mixture is fully moist and the roots are functioning again. It may help to place the plant in a plastic bag to provide humidity to help it recover.
A relative humidity above 50% is preferred to successfully maintain flower production. Provide additional humidity by setting plants on saucers then placing on shallow trays filled with moistened pebbles or use a modest humidifier.
Fertilize African violets once a month going by package instructions or fertilize 1/4 strength for weekly feeding when watering is needed using a balanced African violet fertilizer, so weekly, weakly. Fertilizer salts can build up so transplanting into fresh potting mixture removes the built up.
Violets bloom best in small pots, ideally 1/3 the diameter of the plant's leaf span. Use a peat based potting mixture made up of equals parts peat moss, perlite and vermiculite, or use standard peat based potting mixture. When adding potting mixture do so loosely without packing the soil down on the roots. To determine pot size needed, measure the rosette (center flowers growth), and choose a pot only 1/3 that of the plant. Largest container needed would be 5- 6-inches wide.
Miniature and young trailing types can also be grown in pots, but large mature trailers are best grown in hanging type basket where the stems have plenty of room to root down in pots soil. African violets do best when somewhat potbound. Repot these plants in slightly larger containers only about two months after roots have filled the current containers,
When repotting, remove the outer rig of leaves if the leaf-stalks have been damaged, removing each leaf-stalk by a sharp tug sideways; do not cut stalks away. Break off the entire leaf-stalk because any stub that remains can rot and infect the main stem.
To keep your violet flowering happily, repot once a year or every 6 -9 months. African violets can be divided and sucker growth removed to re-establish a single crown plant.
African violets are easily propagated by leaf cuttings in water or potting medium (may take 8 weeks to see growth from roots in medium). Take firm, medium-sized, healthy leaves and shorten the stalks to 1½". Place foil wrap on and around a glass of water and punch holes for the leaf stalk to be placed through the foil holes into the water or plant them in a moistened rooting medium. Plants can easily be divided and transplanted by carefully pulling apart if good sufficient roots are attached.
To root new cuttings a temperature is needed between 70º and 80º F. Humidity above 50% supports a leaf until roots form well. Use a young but mature leaf from 2nd or 3rd rows in the rosette to produce roots more quickly than an older too mature leaf/stem.
To keep their growth symmetrical, turn plants slightly every week. By the end of each month the plant should receive a complete 360º turn so that all the leaves receive equal amounts of light.
Encourage more flower buds to form by maintaining a single crown plant. Carefully remove any sucker growth as soon as it forms in the leaf axil to prevent overcrowded growth in the pot. If there is an excess of nitrogen fertilizer in the soil, too many leaves will be produced at the expense of flower formation. Remove the outer rows of the largest leaves to promote use of nitrogen and production of flowers.
Wilting leaves can indicate that the plant is too dry and needs water. On the other hand, wilting African violet leaves may also be a sign of overwatering, especially if the plant is in a plastic pot. Soil in plastic pots retains more moisture than soil in terracotta pots, especially during the low light and cooler temperatures of winter (or a cold room). Overwatering can also occur easily when a plant is placed in a pot too large for the root system, which causes the soil to retain moisture too long, resulting in rot. One way to reduce the risk of overwatering is to use terracotta pots. Terracotta is porous and will dry out more easily and so may be a better choice if overwatering is an issue, especially in winter.
Too-wet soil can cause a fungal disease called stem and crown rot or root rot, which causes wilting. To prevent this problem, water only the soil. Use a long-stem watering can and keep the water away from the plant stem as much as possible. Water early in the day, never at night. This rot is difficult to treat, but repotting may help your plant recover. Before you repot, let the soil dry out. Then cut away damaged foliage with a sterile cutting tool and remove the plant from its pot. Carefully remove the old, dry soil. Repot, adding fresh potting mixture, and give proper care. The plant should eventually flower again.
To keep your violet flowering happily, repot once a year or every 6 -9 months.
African violets require bright light preferring to be within 24" of a bright window. If windows aren't available LED lights or fluorescent lights can be used to supplement lighting. Watch how your African violet reacts to the light. If leaf develops long stems that reach up, it desires brighter light. If the plant leaves loose color (bleach) the light is probably too intense (move back a bit).
The Complete Houseplant Survival Manual by 
The Unexpected Houseplant by 
Houseplants and Indoor Gardening by 
