Light and Temperature for Saintpaulia - African Violet
Saintpaulia - African violet needs lights and right temperature to grow, bloom and be healthy.
Proper Light Conditions for Growing African Violets
African violets can grow under natural light (sun), artificial lights or combination of this two. They can't grow and bloom on coffee or dinner table without artificial lights. If you grow your African violets using only natural light, but you want to use your African violet for decoration away from windows because of some occasion (dinner for example), put your blooming African violet on dinner table and than back on it's position right after dinner - African violet can stop blooming if this is done too often or if it is left in 'dark' for day or more ...
African violets can grow on direct sunlight, but they can tolerate it only early in the morning and late during the day. Direct sunlight, especially during summer, will harm African violets. If you have a light meter, correct amount of light (luminosity, illuminance, luminous flux) for African violets is around 10.000 to 12.000 lux (10.000 - 12.000 lumens per square meter or 900 - 1.100 lumens per square foot).
For example, full moon is usually around 0.5 - 1.0 lux, living rooms 50 - 100 lux, offices are around 250 - 500 lux, sunrise or sunset on a clear day is around 400 lux, but full daylight (not direct sun) is around 10.000 - 25.000 lux and direct sunlight is between 32.000 - 130.000 (even 180.000 depending on your location and season) lux. Obviously, African violet plant left outside during summer can receive in a single hour enough sunlight for entire day - this will probably burn the leaves and damage the plant, maybe even kill it.
Best position for African violets is next to the window. During winter, east or south windows are best, while during summer west or north windows provide better growing conditions. If placed on west windows, be sure to protect them from too much direct sunlight (put the shades on the window glass in order to limit the amount of light). It is good practice for African violets and other plants growing next to window to rotate growing pots some 90-180° every time you water them (for example on weekly basis). This way, African violets will grow symmetrically in all directions.
Growing Lights for Indoor Plants
Growing lights for indoor plants can be:
- bulb grow lights
- fluorescent grow lights
- LED grow lights
For single plants, small bulb or LED grow lights are most practical, but there are also grow lights for individual plants based on small fluorescent tubes. For larger areas, light source vary from manufacturer to manufacturer.
Artificial grow lights are maybe best solution for those wanting to have their African violets permanently positioned away from windows or for any other reason don't have their indoor plants next to windows and sunlight. When selecting grow lights for African violets, be sure that it emits light both in blue and red spectrum. Blue light is needed for photosynthesis (strong and healthy leaves and plant in general), while red light is needed for blooming to occur.
During the time, plant will grow and as it grows, plant is closer and closer to light source - again, too much lights can harm the plant. Always read the instructions that come with growing lights, but generally grow lights should be 30 - 35 cm (10 - 12 inches) above miniature African violet plants and around 45 - 55 cm (17 - 22 inches) above standard and large African violets. This of course can be reduced, but observe your plants carefully to prevent any damage due to too much lights.
Simplest solution for artificial African violet lights are two 40 W fluorescent lights some 30 - 35 cm (10 - 12 inches) from plants for about 14 hours per day. Fluorescent lights lose 10-20% of light flux in first one to two years (after that it stays constant), so it is good practice to change one fluorescent light every year. If your Saintpaulias grow happily, change nothing. Again, be careful about light conditions as your plants grow - if your plants are 30 cm from light and they grow 5 cm taller, they are about 16% closer than before and that is increase of 44% in light strength. If your lights are 60 cm above your plants and your plants grow 5 cm taller, plants are 8% closer and that is increase of 19% in light strength. Observe your plants over time and since these changes are slow, you will have plenty of time to react.
Grow lights with timers can be purchased in every garden center or ordered on-line. Read manufacturer's instructions, but generally you will position your plants some 30 - 40 cm (12 - 16 inches) below growing light, program timer when to start artificial light and how long will it be turned on.
For proper growth, African violets also need - darkness. 7-8 hours of dark is needed for development of both leaves and flowers - don't leave your African violets under growing lights over night, it can also prevent plants from blooming and growing properly.
Note: if your African violet won't bloom, than it is not receiving enough light, while too much light can cause other problems, like brittle and yellow leaves with holes ...
Recommended Growing Lights for African Violets and Other Indoor Plants
There are plenty of growing lights on the market today - this is fast growing and expanding market, with LED growing lights often overtaking bulb and fluorescent growing lights in small applications, where higher price of individual (or small batch) light source is not that much important. Growers with plenty of plants wanting to ensure proper growing conditions still often choose fluorescent lights. If you are do-it-yourself person, than you can make your own growing light using various LEDs, bulbs or fluorescent tubes as light sources, just be sure to check light intensity with some light meter - test your lights on limited number of plants for few weeks and if they are happy, other plants will be happy too. If you need growling light for limited number of plants, you can also purchase them on-line. Feel free to check links below (they open in new browser window) and will give you sense about growing lights on the market.
These are two very similar growing light systems for indoor plants and flowers, African violets included.
Only difference is width - 60 cm (2 feet) and 120 cm (4 feet). They both are characterized by:
- easy assembly
- easily adjustable light height for growing plants - great for African violets and other indoor plants that change their height as they grow and for getting an early start with garden vegetables
- sturdy, durable and energy efficient
- T5 high output grow light fixture and bulb
- automatically changes amount of light depending on season, just set season once and internal computer chip starts daylight cycle, simulating nature's clock
- 9-watt, full-spectrum fluorescent bulb mimics sun's rays for optimum growth, recommended for various plants, not only for African violets
- humidity sensor indicates when plant needs water
- pebble tray can hold water for plants needing more humidity around plant leaves
- suitable for plants up to 30 cm (10 inches) tall in 12 - 16 cm (5 - 6 inches) pots.
This artificial light is not suitable for indoor plants that need plenty of lights, but this is not requirement for African violets. Also, setting dawn/sunset can be sometimes problematic - be sure to plug this light in the morning. I am sure that manufacturer has been noted about this 'problem' and that this will be solved in the future (if it is not already solved).
There are many other much more expensive growing lights and complete systems for indoor and outdoor plants, like (links open in new windows, so feel free to check them):
But, before buying such expensive lights, be sure that they are really what you need...
When buying light meters, have in mind that summer light can be up to 180.000 lux strong. If you need light meter for checking indoor conditions (and African violets are indoor plants), go for small and cheap digital light meters. They are reliable and can last for a long time and there is no need for wasting money on professional light meters that costs hundred of dollars. Here are few small and cheap light meters to consider for checking light conditions for African violets and other indoor plants:
On the other hand, if you are investing in high power flowering LED grow light and you have plant line where 2-3 plant lines are illuminated for 8-12 hours per day, then investing in professional light meter can be a smart move - 900W LED grow light can create even up to 200.000 lux of light, so placing plants on proper distance is extremely important.
This is very important not only for people growing African violets, but also for growing small plants like strawberries and herbs indoors, all year long.
An example of such light meter is:
Personally, I don't have a light meter - I watch my plants and if they are happy, I don't change anything. And most of the time, they are happy :o)
Proper Temperature Conditions for Growing African Violets
Optimum temperature for African violets is between 18°C (65°F) and 24°C (75°F). In these conditions with proper lights and fertilizers, African violets will bloom up to 9 months per year, even more.
Temperatures below 16°C (60°F) and above 27°C (80°F) can cause reduced bloom and slowed growth. During winter, African violets can 'survive' 10°C (50°F) for shorter periods of time (for example, over night) if their soil is kept dry. If possible, avoid such conditions, since plants need time to recover and to start growing and blooming.
For plants growing near windows, it is very important to avoid direct contact between leaves and cold glass surface - this can damage leaves significantly. If needed, put some insulator between window glass and plants (thin foam or Styrofoam sheet or at least thick layer of newspaper).
For plants growing next to doors and windows that are opened frequently, try to avoid draft to pass directly across plants. Large temperature fluctuations can be harmful to the Saintpaulias ...
Many growing systems that have artificial growing lights also often have options for additional protection of growing plants, thus allowing setting proper temperature, humidity and light conditions for growing plants.
Such systems can be very expensive, but provide everything that serious grower needs.
General rule is that, if you feel comfortable in the room where African violets are, they will do just fine regarding temperature.