Jill's African Violet Page

African Violets

The African violet (Saintpaulia) is an excellent flowering house plant which can grow and flower in the average home's light intensities.  When natural light is unavalible these plants can be successfully grown under artificial light.  With the large numbers of different varieties, types and colors available, and the ease with which they can be grown makes this an excellent plant for interior decoration of the home.

African violets require about 1000 foot-candles of light for 8 to 12 hours per day for best growth and flowering. However, lower light levels for longer periods of time are also satisfactory. Often, it is possible to tell from the plants appearance whether light levels are satisfactory. If light is too low, leaves are usually deeper in color and thinner than leaves on plants receiving higher levels of light.  Where as, high levels of light cause leaves to be pale or yellowish green, much lighter than normal and some leaves may show dark areas where they have been shaded by other leaves. Growth at high light levels is slowed and plants become more compact, however, although flowering may continue freely for a while it will eventually decrease due to chlorophyll destruction.  African violets should never be exposed to direct sunlight.  These plants can also be successfully grown when the only source of light is from fluorescent lamps. Although incandescent lamps may be used, fluorescent lamps give better results, are less expensive to operate, and produce less heat. Plants grown entirely under fluorescent light should receive approximately 600 foot-candles of light for about 15 to 18 hours per day. This amount of light can be provided by suspending two 40-watt fluorescent tubes 12 to 15 inches above plants. Tubes should be mounted in suitable fixtures equipped with reflectors.

African violets grow best at a night temperature of 65 to 70°F, but will grow satisfactorily at 60 to 80° F.  But if exposed to high temperatures for a prolonged period of time the growth and flowering of the plant will be reduced.  If at all possible, place plants in the coolest place in the home during these periods or in an air conditioned room.

African violets tolerate dry air, but need high humidity for best growth and flowering. Humidity around plants can be increased by setting pots in water-tight metal or plastic trays filled with wet pebbles or sand. Care must be taken to avoid placing pots directly in water to prevent root damage.

Drainage is one of the most important considerations in preparing a soil mixture for African violets. An excellent mixture of readily available materials may be prepared by mixing equal parts (by volume) of soil, sphagnum peat, and horticultural grade perlite. Excellent plants can also be grown in mixtures consisting of equal parts of sphagnum peat moss and perlite. Commercially prepared packaged soil mixtures are also available for African violets. Soil mixtures should have a pH of about 6.0 to 6.5 or be slightly acid for best results.  

Remember drainage, watering frequency, and type of soil when choosing the type of pot to plant your African violet in.  As a general rule plants in clay pots require more frequent watering than those in plastic pots since evaporation is greater. Decorative glazed pots without drainage holes are generally unsatisfactory due to lack of drainage. Remember as well to actually water you plants.  Its not a good idea to let the soil get hard and the plant wilt. You are KILLING your plant if you this! You can water your African violet whichever way you choose. You can do the conventional top to bottom watering, you can try watering from the bottom up, (Just make sure you know how to do this before hand so as to prevent the over watering and killing of you plant.) or you can use wick watering (again, see above warning).  The temperature of the water should be room temperature or slightly warmer to avoid any chance of spotting leaves if water contacts foliage. Chlorinated or fluorinated water, if safe for humans, is safe for African violets.  In other words, it won't kill them if it won't kill us.

If you want or feel the need (or if you plant feels the need) many completely water-soluble fertilizers containing nitrogen, phosphorus, potassium and other required nutrients are sold for use on house plants and African violets. The safest way to apply dissolved fertilizer is to give the soil a normal watering from the top, apply fertilizer from the top and then discard excess water and fertilizer solution that drains from the bottom.  Plant growth and color often indicate need for fertilizer. A gradual loss in leaf color combined with a reduced growth rate usually indicates that fertilizer is needed. If in doubt as to whether plants need additional nutrients, fertilize one or two and wait about 10 days to see how they react. If plant growth is evident and they become darker in color, the rest of the plants may be fertilized.

African violets may be propagated easily by leaf cutting, and about 6 to 9 months are required to obtain flowering plants. Any leaf is alright if healthy and firm. Remove the entire leaf with petiole (leaf stem) by snapping or cutting it off at the stem of the plant and trim the petiole to about 1 to 1 1/2 inches in length. A combination of half vermiculite and half sand, by volume, makes an ideal propagating medium or the soil used for growing plants may be used.  Roots normally appear at the petiole base in 3 to 4 weeks under good conditions and leaves of the new plants appear at the medium surface 3 to 4 weeks after root formation.  Old multiple-crown plants may often be successfully propagated by division. Carefully cut each crown away from the plant so that each plant has its portion of the root system. Each division is then potted in the soil mixture.

Old plants often develop a short stem which cause them to have a ``leggy'' appearance. Usually such plants may be successfully re-rooted by cutting the plant off at the soil level and inserting the old stem in the same medium used for rooting leaf cuttings.

New plants brought into the home should be examined thoroughly for signs of insects and diseases and kept separated from other plants.  Actually if you buy the plants you should check this out first.  If you do decide to buy the plant(s) and bring them home be sure they still appear healthy at the end of about 6 weeks.  It is usually safe then to set them with the the rest of your plants.

Control of most insects and mites can be obtained with insecticidal soap sprays. Mealy bugs may be controlled by mixing alcohol with an equal amount of water and touching each insect with a cotton swab dipped in the solution.  Cyclamen mites which causes a severe stunting of plants is difficult to control and where only a few plants are concerned, they should be discarded. If many plants are affected, Kelthane sprays may be used. Be sure to read and follow all label directions on pesticides used on african violets.

Root diseases usually result from over watering of plants. Symptoms may not show up on the leaves until severe root damage has occurred. In most cases with root diseases or damage the best control is to discard the plant and purchase new healthy ones.

Some problems caused by cultural factors include ring or leafspot and petiole rot. Yellowish rings, spots or streaks on the upper surface of leaves are caused by cold water touching relatively warm leaves. This can be avoided by using water at room temperature or slightly warmer than leaf temperature. Petiole rot occurs when petioles touch the edge of the pot and develop brown, sunken areas at points of contact. The injury is localized and does not cause the petiole to rot unless disease organisms enter the wound. This trouble is the result of chemical injury caused by the accumulation of soluble salts at the pot rim of clay pots. This problem can be reduced by using fertilizers sparingly and applying sufficient water to thoroughly saturate the soil. When water is applied to the soil surface, excess water and the salts will drain out the bottom of the pot. Petiole rot can also be avoided by waxing the pot rim or covering it with aluminum foil.

Various disease organisms may affect african violets from time to time, but adequate spacing of plants, use of sterilized soil, provision for good air circulation, prompt removal of faded flowers and unhealthy leaves, and control of thrips and mites are all important preventative measures.  Please also just use your good old common sense.




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