The African violet’s long flowering period, attractive rosette of leaves, convenience in handling, and ease of propagation have made it one of the most popular indoor plants.
From the original purple flowers, growers have produced white varieties and many shades of blue and pink, also bicolors, in singles, doubles, and semi-doubles, on large plants and dwarfs, with leaves variable in color and markings.
They are all fastidious and need understanding care.
African violets will not grow well when the night temperature falls below 60 degrees, and do best when this is between 65 and 70.
The day temperature is about 10 degrees higher. Below 60 degrees, growth is poor, and a temperature below 50 means eventual death.
The plants, however, will survive temperatures as low as 50 or as high as 100 degrees over short periods.
Coming from the jungle, they like humid conditions, although tolerating fairly dry air.
Moist air can be obtained to some extent by sitting the plants on a bathroom or kitchen shelf, or placing the pots on pebbles or gravel in a shallow tray with a little water in the bottom.
Or the pot can be placed inside a larger one and the gap filled with damp moss.
An occasional spraying with tepid water not only cleans the plants but also helps humidity.
As a general rule, water when the soil feels slightly dry to the touch but before it hardens.
Methods of watering are the subject of argument, but basically any method is satisfactory provided the soil is kept moderately moist and the water is of room temperature or slightly higher.
Plants can be watered from the top or bottom (by placing pots in a saucer of tepid water).
Watering by using wicks is also satisfactory.
Fairly good light is required, but direct sunlight should be avoided, except a little early-morning sun in winter.
Long stalks and thin leaves mean insufficient light; if the light is too strong the growth becomes more compact but less vigorous and the leaves get paler.
Plants can be grown successfully in artificial light (12 to 14 hours a day), especially fluorescent light.
Soils should be open and have plenty of humus. A good general mixture is 2 parts loam, 2 parts well-rotted manure or leaf mold, and 1 part sand.
Another satisfactory mixture used consists of 1 part loam, 2 parts leaf mold or peat moss, and ½ part sand.
It is desirable to sterilize the mixture and pots before using. Moisten the soil and place it in an oven at over 180 degrees for an hour or two.
For small plants use 2½-inch pots, shifting to 2-inch and 4-inch pots. Take care not to cover the crown with soil.
CARE AND ATTENTION
African violets are easily broken or bruised, and need cleaning.
Outer leaves resting on the pots may rot, due to roughness of the edges, moisture, or accumulation of salts. Cover the edges of rough pots with paraffin, sealing-wax, or plastic tape.
The leaves need dusting regularly. Use a soft brush. Spraying with lukewarm water, using a fine sprinkler, also helps.
Don’t overdo the fertilizer. A little and often is the best guide.
African violets are most effective when kept to a single crown. Side buds or suckers can be removed with a blunt pencil.
Old plants which have been allowed to develop several crowns can be taken from the pots and the crowns gently removed, preferably with some roots, and potted.
Leaf cuttings are another method. Take a healthy leaf from the upper row, removing it close to the crown; then with a razor-blade cut the stalk ¾ inch or 1 inch below the leaf, and insert the stalk into the rooting medium.
Water well, cover with a glass jar or plastic, place in moderate light, and keep just moist. A good mixture is equal parts of peat moss and sand.
Leaf cuttings (with longer stalks) can also be rooted in water. Place cardboard, foil, or waxed paper, punched with holes, over a jar, and insert the stalks through the holes so that about 1 inch is in the water.
When roots appear, after 2 or 4 weeks, change the water, adding a small amount of soluble fertilizer. When the cuttings are well rooted, transfer to small pots.
One of the commonest troubles in African violets is not due to disease but to faulty handling. Yellow spots on the leaves are usually caused by watering with cold water, or by exposing the leaves to sunlight while still wet.
Other troubles are nematodes, which can be controlled only by soil fertilization. Mealy bugs, thrips, mites, and mildew may also affect the plants. If there is only a light infestation of mealy bugs, these may be wiped off gently with cotton wool, or sprayed with Malathion or a DDT preparation (which also will control mites and thrips).