While technically not a violet at all, the African violet (Saintpaulias sp.) may be the most cherished houseplant of the century.
It’s not surprising why; they have modest light requirements, take up little space, are easily propagated and – most of all – they produce wonderful flowers. A healthy plant can be in bloom nearly year round. Let’s take a deeper look at this classic houseplant and what it needs to thrive in your care.
Originating from Tanzania and Kenya, the genus Saintpaulias holds over a dozen species (not including popular hybrids), the most important of which is Saintpaulia ionantha, the original “violet” described in 1894 that started it all. The African violet’s native habitat lies predominantly in the montane rainforests associated with the higher reaches of Eastern Arc mountains in eastern Tanzania, a particularly rich area of cloud forest that holds a wealth of globally-significant biodiversity and boasts high levels of endemism. Unfortunately, the future status of the African violet and other members of Saintaulia in the wild is tenuous at best.
African Violet Light Requirements
African violets are adapted to the shady nooks and moist microclimates found along rocky slopes, outcrops, limestone formations and even the protected side of tree trunks. African violets are averse to direct, hot sunshine and are well-known for being able to grow and bloom in lower light than most flowering species.
However, they do need a certain degree of moderately bright indirect light. Virtually any windowsill in the home can be used, so long as the plant does not receive direct light, which is just too hot and intense for this plant’s leaves. Early morning direct sun from the east is OK. Remember that as soon as you move away from a window light levels drop very quickly, so keep them close to windows, especially if using a much dimmer north-facing window. Rotate your violets every few days to give all sides of the plant ample light; if you don’t they will bend toward the light and it will ruin their attractive rosette shape.
An alternative to sunlight that most professional growers opt for is florescent lighting. Given their preference for cool light and their short stature, African violets are perhaps one of the most suitable houseplants for culturing under florescent light. Artificial lights afford a degree of control over growth and temperature that is hard to match, and comes with the added benefit of ensuring an optimal and consistent photoperiod. If you go this route, its most practical to use a cool white florescent tube that sits about 8 to 12 inches from the top of the plant, and leave it on for about 14 hours per day. Any inexpensive indoor florescent grow light with enough wattage that can accommodate several plants will work fine.
Potting Soil for African Violets
There are as many recipes for “secret” potting soil for this species as there varieties of the plants themselves. However, the basic aim is to achieve a soil high in organic matter that drains quickly and is light enough to allow oxygen to enter while remaining slightly moist. Most African violet enthusiasts will be quick to decry commercial potting mixes, but the reality is that most good African violet soil-less mixes are fine. What you want is a mix that is composed primarily of sphagnum peat moss. If you must tinker with the soil, a good compromise is to use a commercial potting soil and mix it with some more peat moss and coarse perlite, in equal parts by volume.
African violets do best a slightly acidic soil, but you don’t need to worry about that when preparing soil if using a largely peat moss-based mix, which should be plenty acidic on its own.
Watering Your African Violet
There are two schools of thought on watering African violets, each of which has their respective virtues.
On the one hand, traditional houseplant care generally favors watering from the top down, so water always freely runs out the bottom of the drainage holes where it can be discarded. For me, this is and will always be the way I teach people to water their plant material. For starters, this method discourages the build up of salts and minerals that are in tap water, fertilizers and soil mixes. These minerals (especially if you have hard water) can easily accumulate and create alkaline soil conditions or simply become saline to the plant (by the way do not used softened water on any houseplant).
On the other hand, many serious African violet enthusiasts swear by wick or self-watering systems, whereby the pot is arranged in such a way that water is taken up into the root ball via capillary action. The thought behind this system is that it keeps the soil uniformly and consistently moist, without water-logging it. Of course, it also has the benefit of virtually eliminating the fear of missing a watering, or the stress from occasional underwatering.
I think that wick systems are fine and I am not against them. However, there are some important caveats. First, you must understand the chemistry of the water you are using. If your water is hard and alkaline, as it is here throughout much of the southwestern US, I would not recommend wick watering. Hard water in a wick system is a great way to accumulate minerals and salts in the root zone as the pure water evaporates off. Look for hard water stains on your glassware if left to air-dry. The same thing will happen in the soil, and white crusty material around the wick and surface of soil is a telltale sign of mineral buildup. Beyond potentially causing osmotic stress (in a severe case wilting), this will almost certainly raise soil pH to levels that “lockout” trace metals, most notably of which is iron. In other words, a bad idea.
If, however, you have access to naturally pure water (i.e., with low total dissolved solids and a pH of around 7.0) or are using distilled or reverse osmosis water, then I am all for it. In this case, the water will not add any significant mineral content to the soil or alter pH, so there is much less need for the flushing obtained from top-watering. Nevertheless, fertilizer residues will still accumulate over time so you should top-water ever couple weeks to leach them out and restore balance.
Potting & Repotting African Violets
African violets do not need particularly large pots at any point in their life and most standard-sized mature plants of 10″ inches in width or greater can be kept in a 4 inch diameter pot. If anything, plants in smaller pots tend to be more vigorous and produce more frequent blooms compared to over-potted specimens.
The type of pot you use is generally up to you, but must have adequate drainage holes that are covered with rocks or screening to prevent loss of soil. Most people that utilize wick watering prefer plastic pots, since they are non-porous and result in a more consistent watering regime with less loss to evaporation.
When repotting, make sure that the soil is slightly damp, as this should help the plant slip out of the pot without too much trouble. I would not disturb the plant’s roots unless they are very well coiled around due to being slightly pot bound, in which case I would slowly massage them apart and score the outside of the rootball slightly before putting into new soil. Make sure to brush/blow off any soil or dirt that settled on the leaves as this can promote fungus and/or leaf discoloration.
Proper Temperature for African Violets
African violets thrive in ordinary room temperatures, just stay away from extremes. Temperatures below 50F and above 90F are to be avoided, and plants are easily shocked if watered with cold water. Letting your water sit out overnight brings it to room temperature and also releases chlorine, thus killing two birds with one stone.
If you’re interested, it’s always a good idea to set a small thermometer next to the plant, either on the windowsill or at leaf-level if using florescent lighting, to see exactly what the temperatures are within the plant’s micro-climate and make adjustments as necessary. You may be surprised what you learn.
African Violets & Humidity
Like so many houseplants hailing from balmy equatorial zones, your African violet likes more humidity than is wise to maintain at home. The ideal relative humidity is between 50 and 70%; neither of which is recommended indoors since this is a great way to grow molds and mildew, along with your African violets.
The compromise (unless you are blessed with high humidity naturally) is to either set the plant above a tray of water and pebbles, or very gently mist the plants. Misting is a delicate operation with these hairy-leaved plants and is best avoided if other avenues exist, since it can leave water spots or foster conditions for pathogens. An added twist to the tray/pebbles option is to sit the plant on a screen/rack over a basin of water in which an aquarium air pump and air stone is installed. The very fine rising column of bubbles will create a steady stream of humidified air. Just be sure that the plant is high enough above the water so that it does not actually come in contact with any fine spray from the aerator.
Fertilizing Your African Violet
Any plant that blooms as consistently as an African violet needs regular feeding. In fact, flowering is a highly energy-intensive process for any plant. So, even if sunlight, water and humidity are not limiting, a lack of nutrients and/or trace elements can quickly put the brakes on blooming, even if the plant seems otherwise healthy.
As far as what fertilizer to use, there are many good African violet specialty liquid fertilizers that should do the job. However, with regard to feeding schedule, you have choices. You can either adhere to the recommended manufacturer’s dose and schedule, or you can opt of a continuous feeding approach, whereby the recommended dose is cut to between 1/8 and 1/4 the full dose, but delivered each time the plant is watered. The continual feed method is an especially good option for self-watering systems.
African Violet Propagation
By far the best way to propagate African violets is through leaf cuttings.
This is a very easy process, especially once you’ve done it a couple times. First, select a healthy, young leaf toward the middle of the rosette – something semi-mature but with a good size. Snap it off at the soil level and then angle-cut it with a razor blade just above the break. Put the cut end of the leaf in some water while we prepare the soil.
Either buy a light seed starting medium, or make your own by combining equal parts perlite and vermiculite and filling a small 2-inch pot. Moisten the medium with water (I like distilled or reverse osmosis water for this) containing a very dilute concentration of liquid fertilizer (1/8 manufacturer’s recommended strength). Make a hole with the blunt end of a chopstick or pencil and insert the cut-end of the leaf. Gently firm the medium around the cutting and water it again, and let the medium drain thoroughly.
Take the pot and stick a couple Popsicle or other small sticks on both sides of the pot, and gently place a sandwich bag or any other fine, clear plastic over the cutting and pot, making sure that the cutting does not touch the plastic. This will elevate humidity and help spur root production. Take the plastic off every couple days or so for 10 minutes to ventilate. Now wait until new plantlets begin to form.
When a plantlet has several leaves and is beginning to form a mini-rosette, you can gently knock off the medium and divide them. Use a sharp razor when making cuts and try to avoid damaging roots when doing so. Pot the new plantlets in their own 2″ pots and treat as adults.
Another option is rooting cuttings in water; however, while this may seem easier, it ends up being the slower route. The roots created in water tend to be very weak and generally need to be shed in favor of terrestrial-adapted roots anyway. So save yourself and the plant some time and start your cuttings directly in soil.
African violet photo credits (in order of appearance):
“African violet” by Leslie under CC BY 2.0
“African violets” by Ann under CC BY 2.0
“African violet” by sean mason under CC BY 2.0
“African violet show” by walrus36 under CC BY 2.0
“African violet roots and leaf starts” by Madaise under CC BY-ND 2.0