African Violets (AVs) are popular flowering houseplants, prized for their velvety leaves and near-constant display of color. To encourage continuous blooming, AVs require a steady supply of nutrients because the small volume of potting mix they use quickly becomes depleted. These delicate plants are highly sensitive to concentrated chemical salts, so their feeding regimen must be precise and gentle. A successful strategy focuses on providing a balanced diet tailored to their unique needs.
Choosing the Right Fertilizer
The best fertilizer for African Violets is one specifically formulated for them, typically a water-soluble powder or liquid. These specialized foods feature a balanced NPK ratio, representing the percentage of Nitrogen (N), Phosphorus (P), and Potassium (K). While general houseplant fertilizers use high nitrogen, AVs thrive on formulas like 14-12-14 or 12-36-14, where the second number (Phosphorus) is elevated to encourage robust flowering.
Select a fertilizer where the nitrogen source is not urea, as urea can cause root burn. Look for gentler nitrogen sources like ammonium nitrate. Water-soluble options are recommended because they dissolve completely, ensuring absorption and preventing clogging in self-watering systems. Slow-release granular fertilizers are discouraged because they make nutrient control difficult and often lead to over-fertilization and salt build-up.
Establishing a Consistent Feeding Schedule
African Violets benefit from the “weakly, weekly” approach, applying a highly diluted fertilizer solution with nearly every watering. This method mimics slow, steady nutrient availability and prevents the nutrient shock associated with infrequent, high-dose applications. A full-strength dose, even monthly, is too harsh for the plant’s delicate root system.
Maintain this consistent feeding schedule during the active growing period, typically spring through fall. A common dilution rate is one-quarter of the amount recommended on the package, or approximately 1/8 to 1/4 teaspoon per gallon of water. When light levels drop during winter, the plant’s growth slows, and you should reduce the feeding frequency or concentration.
Correct Application Techniques
The most effective way to deliver the diluted nutrient solution is through bottom watering. This ensures the roots draw the water upward evenly through capillary action. To use this method, place the potted African Violet into a container holding the solution, allowing it to soak for 30 to 45 minutes until the topsoil feels moist. This technique keeps the leaves and the plant’s crown dry, preventing the leaf spotting and rot that occurs when water sits on the foliage.
If you top water, pour the solution directly onto the soil surface, avoiding the leaves entirely. Use lukewarm water, as cold water can shock the root system and cause brown or yellow spots on the leaves. Regardless of the method, occasionally flush the soil with plain, lukewarm water. Doing this once a month helps wash away accumulated mineral salts from the fertilizer, preventing the soil from becoming toxic to the roots.
Troubleshooting Over-Fertilization and Salt Build-Up
Over-fertilization causes a build-up of mineral salts in the potting mix, which can burn the root system. Visible signs include brown or crispy leaf edges, a tight and stunted crown of new leaves, and a white or yellowish crust appearing on the soil surface or pot rim. Crystals may also be visible clinging to the leaves or the pot rim.
The immediate remedy for salt build-up is to thoroughly flush the soil. Pour a large volume of plain, lukewarm water through the pot multiple times, allowing it to drain completely to wash away the excess mineral salts. Use water equivalent to at least four times the volume of the pot for a deep clean. After flushing, wipe away any visible crusts and wait about a week before resuming the highly diluted feeding schedule.