How many hours of grow light do African violets need? About 12–16 hours a day, with at least 8 hours of darkness. With grow lights for African violets, Iowa State suggests hanging a fluorescent fixture 8–10 inches (20–25 cm) above the plants for 12–16 hours. University of Florida says plants grown entirely under lights need about 600 foot-candles for roughly 16 hours.
Key takeaway: African violets are one of the few flowering houseplants that often bloom better indoors under lamps than on a windowsill. Colorado State University’s PlantTalk says they grow well under artificial light and often bloom more than in natural light. Grow lights for African violets only work if you get three things right: distance, hours and the darkness period.
| Factor | Guideline | Source |
|---|---|---|
| Hours for grow lights for African violets | 12–16 h; about 15–16 h if lights are the only source | Iowa State; UF; CSU |
| Darkness | At least 8 hours | UF/IFAS |
| Fluorescent distance | 8–10 in (20–25 cm), or 12–15 in (30–38 cm) for two 40 W tubes | Iowa State; UF; CSU |
| Light level (lights only) | About 600 foot-candles | UF; CSU; Purdue |
| Window light target | About 1,000 foot-candles, no direct sun | UF/IFAS |
| Night temperature | 65–70°F (18–21°C) | UF; CSU; Purdue |
Do You Need Grow Lights for African Violets?
Not always, but they often bloom better with them. University of Florida (UF/IFAS) says African violets need bright light of about 1,000 foot-candles for best growth and flowering, but no direct sunlight. Purdue Extension adds that violets need more light than most growers think. When a bright north or east window is not available, Iowa State says they can be grown successfully under fluorescent lights.
Growing them in water? See our African violets water culture guide.
How Far Should Grow Lights for African Violets Be?
Closer than you might expect. Iowa State Extension says a fluorescent fixture suspended 8 to 10 inches (20–25 cm) above the plants should provide enough light. UF, CSU and Purdue say two 40-watt fluorescent tubes hung 12 to 15 inches (30–38 cm) above the plants provide roughly 600 foot-candles, enough to grow violets entirely under lights.
- Fluorescent fixture: 8–10 in (20–25 cm), per Iowa State.
- Two 40 W tubes: 12–15 in (30–38 cm), per UF, CSU and Purdue.
- LEDs: follow the maker’s chart and watch the leaves.
How Many Hours Should Grow Lights for African Violets Run?
About 12 to 16 hours. Iowa State recommends 12 to 16 hours a day under fluorescent lights. UF says violets need 8 to 12 hours of light, up to 16, plus 8 hours of darkness to bloom, and about 16 hours when lamps are the only light. CSU and Purdue suggest 15 hours. UF notes a plant given too short a period does poorly even with the right intensity.
A plug-in timer keeps this consistent; our hydroponic light schedule guide explains photoperiods.
How Do You Know Grow Lights for African Violets Are Too Weak?
Look at the leaves. UF says leaves that are thin, deep green and reach upward mean light is too low, and the plants may flower poorly or not at all. Iowa State describes thin, blue-green leaves with long petioles. CSU adds that underlit plants may keep normal color but rarely bloom, with thin leaf blades and elongated leaf stems.
- Leaves: thin, deep or blue-green, reaching up.
- Stems: long, stretched petioles.
- Flowers: few or none.
- Fix: lower the light or add an hour.
How Do You Know Grow Lights for African Violets Are Too Strong?
Pale, tight growth. UF says excessive light makes leaves pale or greenish-yellow, slows growth and makes plants very compact, and flowering may decrease. Purdue says too much light gives stunted plants with short petioles and small, crinkled, leathery leaves. Iowa State describes small, crinkled, yellow leaves on short petioles. Raise the light or cut the hours.
- Leaves: pale, yellow-green, small or crinkled.
- Crown: tight and bunched.
- Fix: raise the light or remove an hour.
What Type of Grow Lights for African Violets Works Best?
Fluorescent tubes and LEDs both work. UF says fluorescent lamps beat incandescent bulbs, cost less to run and produce less heat, and notes newer options such as T5 and LED grow lights. CSU recommends wide-spectrum fluorescent tubes. The African Violet Society of America (AVSA) shares member setups using T12 tubes, LED shop lights, and mixes of warm and cool bulbs.
Compare fixtures in our full-spectrum grow lights guide.
How Do You Switch to LED Grow Lights for African Violets?
Start short and adjust. One AVSA grower who converted to LED fixtures advises running new LED lights for only 9 hours at first, then adding an hour at a time if the leaves reach upward, because it is better to start low than risk tight centers. The grower notes LED light is strongest directly under the fixture, so turn plants often.
- Run new LEDs about 9 hours a day.
- Watch the plants for a few weeks.
- Add one hour if leaves reach upward.
- Cut back if centers grow tight.
- Turn pots so all sides get light.
What Else Helps Grow Lights for African Violets Work?
Steady warmth and humidity. UF says African violets prefer nights of 65–70°F (18–21°C) and grow satisfactorily at 60–80°F (16–27°C), while Purdue says growth and flowering slow above 80°F (27°C). UF and CSU recommend high humidity, such as setting pots on trays of pebbles and water. Our grow lights for indoor plants guide covers shelf setups.
FAQ About Grow Lights for African Violets
How long should grow lights be on for African violets?
About 12–16 hours a day.
Do African violets need darkness?
Yes, at least 8 hours a day, per UF.
How far should lights be from African violets?
About 8–10 inches (20–25 cm) for a fluorescent fixture.
Can African violets grow under LED lights?
Yes; start around 9 hours and adjust.
Why are my African violet leaves reaching up?
They need more light.
Why are the leaves pale and crinkled?
Too much light.
Sources
- UF/IFAS Extension — African Violets (MG028)
- Colorado State University Extension — African Violet (PlantTalk 1301)
- Purdue University Extension — African Violets (HO-10)
- Iowa State University Extension — How Much Light Does an African Violet Need?
- African Violet Society of America — Lighting Options
- Photo credits (Wikimedia Commons, edited with titles): African violet (Saintpaulia) by Mk2010 (CC BY-SA 3.0); African Violet Blooms by Sluglife6826 (CC0); Saintpaulia ionantha by RobertoMM (CC BY-SA 3.0)