African violet

About African violet

African violets are small, fuzzy-leaved rosettes from the coastal woods of Tanzania that can flower in every month of the year on a windowsill or under a shop light (NC State, UGA). Hundreds of varieties come in blue, purple, pink, red-violet and white, single or double, from micro-miniatures to plants over 16 inches across. They are fussy about only a few things: steady warmth, room-temperature water kept off the leaves, and enough light.

Hardy outdoors only in zones 11-12 (NC State); it is grown indoors everywhere and is usually kept inside year-round, since nights below 60 F stunt it (NC State, UGA).

When to plant

Timing is counted from your average last spring frost (and first fall frost). Sow & Tell works out the actual dates for your ZIP code.

Usually bought as a blooming nursery plant or started from a leaf cutting, which gives a flowering plant in about 10 months (UGA, Iowa State).

Growing it indoors

• Light: Bright light with no direct afternoon sun, within 3 ft of a window (Clemson); MU Extension prefers a north window, and under two shop-light tubes 6-12 in above the leaves for 14-16 hours a day it blooms year-round (Clemson, UMN).
• Water: Keep the mix moist but let the surface dry before watering again, using room-temperature water either from the bottom (set the pot in 1 in of water until the surface is damp, then drain) or from the top with the leaves kept dry (NC State, Clemson, UMN). Cold water on the leaves leaves white rings, and a constantly wet pot brings crown and root rot, the main killer.
• Humidity: It tolerates ordinary room humidity but does best at 40-60 percent, so group plants or use a pebble tray; don't mist the leaves (UMN, UGA).
• Temperature: Nights of 65-70 F and days up to 80-85 F suit it; below 60 F growth stunts and leaves deform, and a cold windowsill or a draft on wet leaves chills them (Clemson, NC State, UGA, MU Extension).
• Feeding: UGA feeds a water-soluble fertilizer such as 20-20-20 at a third to half the label rate every 4-6 weeks; UMN feeds an African violet fertilizer at quarter strength with every watering and flushes with plain water monthly; either way, feed after watering, never a dry plant.
• Repotting: Once a year into fresh mix, usually the same size pot or one size up, with the crown set a quarter to half inch below the rim; divide plants that have grown extra crowns (UMN, UGA).

Soil

A light, well-drained mix such as equal parts potting soil, peat and perlite, or a soilless African violet mix at pH 6.2-6.5, in a pot with a drainage hole (Clemson, UMN).

Pot in a light, well-drained mix of equal parts potting soil, peat and perlite, or a soilless African violet mix at pH 6.2-6.5 (Clemson, UMN).

Feeding

• Year-round while it is growing and blooming: water-soluble African violet or balanced fertilizer such as 20-20-20, diluted. UGA: a third to half the label rate every 4-6 weeks after watering; UMN: a quarter of the label rate with every watering, with a plain-water flush once a month. Don't feed newly rooted cuttings (UGA).

Too much fertilizer shows as rusty, brittle leaves and a tight center; flush the pot with plain water and feed every other watering instead (UMN).

Harvest

Can bloom year-round under good light, in flushes that last 3-6 weeks (Clemson); snap off spent flower stems at the base and keep the crown to a single rosette.

Varieties (12)

NC State names 12 cultivars by size class; hundreds exist.

Pests to watch for

Mealybugs, Cyclamen mite, Thrips, Aphids

Diseases and problems

Root and crown rot, Crown rot, Gray mold (Botrytis), Ring spot (cold water)

In the kitchen

Safety: Not listed as poisonous to people or pets (NC State, ASPCA).

Pets: Non-toxic to dogs, cats and horses (ASPCA, listed as Saintpaulia spp.).