I'm an avid fan of African violets. When I first learned about them, I always assumed they were fussy plants that you only purchased for their lovely flowers. Once the flowers dropped, well, you just tossed them. In the past year, I learned they will flower profusely all year long when you provide them with all the appropriate conditions. What does it take to keep them alive and flowering? Houseplant expert Darryl Cheng, the author of The New Plant Parent and creator of House Plant Journal, shares his pro tips on how to keep your African violets looking great!
It's All About the Light
Lighting is the trickiest thing when it comes to growing African violets. They need bright light to bloom but do not tolerate hot, direct sun. How can you tell if your plants are getting enough or too much sunlight? If you notice the leaves are very dark green, and the stems are leggy, it's not getting enough light. If the leaves are light or have beached/white spots, it's getting too much.
"Don't judge your success with these plants based only on how much they bloom," says Cheng, "I derive joy from the overall plant, but if you want maximum blooms, the plant will need to be right on the windowsill of your largest, sunniest window - minimum two or three hours of direct sun."
Suppose you lack the proper natural light, no worries! "I personally don't have windows that give me two to three hours of direct sun," explains Cheng. "I use a powerful grow light kept at about one foot away for 14 hours a day." If using grow lights, make sure you give the plants at least eight hours of darkness too. This helps them produce flowers.
Water Them Correctly
African violets prefer moderately moist soil. "You should watch for the soil to become almost halfway dry before thoroughly watering," says Cheng. "Avoid letting the soil become completely dry, but do not aim to keep the soil soaking wet at all times."
Make sure the water is at room temperature before you water the plants to avoid shocking the roots. Another tip is to allow tap water to sit overnight. This will ensure the chlorine evaporates and the water isn't too cold before you water. This method is also suitable for all your other houseplants.
Some enthusiasts recommend you should never get African violet's leaves wet. This is, in part, because the leaves are susceptible to rot if kept in high humidity. So, it's often advised to water the plants from the bottom to avoid getting excess water on the foliage. As long as use a slender spout watering can to water directly in the soil and the plant has excellent air circulation, the leaves will be fine.
All plants need food to thrive, and fertilizing your African violets will help them flower. Cheng says that using a fertilizer with a higher phosphorus (P) generally encourages flowering.
"Fertilizer ratios are listed as nitrogen, phosphorous and potassium. A higher P fertilizer will have numbers in the ratio 1-2-1 or even 1-3-1, for example, or 8-14-9," explains Cheng. "Notice the ratios don't have to be exact." As long as the middle number is the highest, that will indicate the fertilizer has a higher phosphorus level.
You can also use a specially formulated liquid African violet fertilizer at one-quarter strength every time you water or at full strength every two weeks during the active growing season (spring and summer). Don't go overboard—over-fertilizing is a more common problem than under-fertilizing.
African violets like it snug when it comes to pot size. The pot should only be about one-third to half the diameter of the plant. For example, if your plant is about seven to nine inches wide, the pot only needs to be three inches wide. The proper pot size will promote blooming. Don't go too deep, either. Shallower pots are better for drainage and root aeration.
Finally, only repot the plant in fresh soil once a year and use an African violet potting mix or a well-draining all-purpose potting soil.
Appreciate the Foilage
Even if you can not get your plants to reflower, they make exciting foliage plants. "African violets are interesting plants not just for their flowers," says Cheng, "Their leaves form a beautiful rosette pattern and can be propagated. With excellent light, a whole new plant can develop from one leaf." Keep the foliage looking great by dusting periodically with a small, soft brush.